diff --git a/AGENTS.md b/AGENTS.md
index ddc447d8..d81feeaa 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -345,6 +345,35 @@ The TODO.md should be:
 
 - **Global `app` variable**: In Obsidian plugins, `app` is a globally available variable that provides access to the Obsidian API. It's automatically available in all files without needing to import or declare it.
 
+### Picking the right `document` / `window` (popout-window safety)
+
+Obsidian supports pop-out windows. The plugin loads in the main window but views can live in any window. Picking the wrong `Document` / `Window` produces stale references, off-screen popovers, listeners on the wrong window, or DOM nodes that never render. Use this decision order:
+
+1. **`element.doc` / `element.win`** — preferred. Obsidian augments every `Node` with `.doc: Document` and `.win: Window` that always reflect the element's current owner. Use whenever you have any DOM node in scope (a ref, an event target, a component's container, a `Range`'s `startContainer`).
+   - `containerRef.current?.doc.addEventListener(...)`
+   - `range.startContainer.win.innerWidth`
+   - `editor.getRootElement()?.doc`
+2. **`global activeDocument` / `activeWindow`** — fallback only. These point to whichever window is _focused right now_. Correct semantics for actions that follow user focus (e.g., the AddImageModal file picker; selectionchange registration at plugin load), but wrong when the action belongs to a specific view (a chat in a popout while the user clicks back to the main window).
+3. **`document` / `window` globals** — almost always wrong. They are aliases for the main window even when the user is interacting with a popout. Avoid in new code. If you find yourself reaching for them, it's a sign the surrounding code should be taking a `Document`/`Window` parameter or deriving from a DOM ref.
+4. **`element.ownerDocument`** — works (standard DOM), but prefer `.doc` for consistency with the codebase. They return the same `Document` for any mounted `HTMLElement`. `.doc` is shorter and typed non-nullable.
+
+**Listeners that may outlive a window migration:** capture the `Document` / `Window` at registration and remove on the same one:
+
+```ts
+const doc = containerRef.current?.doc;
+if (!doc) return;
+doc.addEventListener("keydown", handler);
+return () => doc.removeEventListener("keydown", handler);
+```
+
+Do **not** rely on `activeDocument` at registration _and_ removal — it can shift between the two calls if focus moves.
+
+**View migrated to a new window:** for a view that owns React or other long-lived renderers, register `this.containerEl.onWindowMigrated((win) => { ... })` in `onOpen`. The callback fires when Obsidian reparents the element into a different window's document. Tear down and rebuild the renderer there so it captures the new window. Save the returned destroy function and call it in `onClose` to avoid leaks. `CopilotView` is the canonical example — it unmounts and recreates the React root on migration so Lexical re-binds to the popout's window.
+
+**Cross-realm `instanceof`:** popout windows have their own `Element`, `MouseEvent`, etc., so standard `instanceof` checks fail across windows. Use Obsidian's `element.instanceOf(HTMLElement)` and `event.instanceOf(MouseEvent)` when checking type across realms.
+
+**Tests (jsdom):** `jest.setup.js` polyfills `Node.doc` / `Node.win` so plugin code using these properties works under jsdom. Don't add `instanceof` guards that depend on the Obsidian-augmented globals without considering the test environment.
+
 ### Architecture Migration Notes
 
 - **SharedState Removed**: The legacy `src/sharedState.ts` has been completely removed
diff --git a/__mocks__/obsidian.js b/__mocks__/obsidian.js
index 73c135e7..c6959999 100644
--- a/__mocks__/obsidian.js
+++ b/__mocks__/obsidian.js
@@ -52,7 +52,7 @@ module.exports = {
     },
   })),
   ItemView: jest.fn().mockImplementation(function () {
-    this.containerEl = document.createElement("div");
+    this.containerEl = window.document.createElement("div");
     this.onOpen = jest.fn();
     this.onClose = jest.fn();
     this.getDisplayText = jest.fn().mockReturnValue("Mock View");
@@ -61,7 +61,7 @@ module.exports = {
   }),
   Notice: jest.fn().mockImplementation(function (message) {
     this.message = message;
-    this.noticeEl = document.createElement("div");
+    this.noticeEl = window.document.createElement("div");
     this.hide = jest.fn();
   }),
   TFile: jest.fn().mockImplementation(function (path) {
diff --git a/jest.setup.js b/jest.setup.js
index 97b5d944..6be58919 100644
--- a/jest.setup.js
+++ b/jest.setup.js
@@ -1,5 +1,25 @@
+/* eslint-env browser */
 import "web-streams-polyfill/dist/polyfill.min.js";
 import { TextEncoder, TextDecoder } from "util";
 
 global.TextEncoder = TextEncoder;
 global.TextDecoder = TextDecoder;
+
+// Polyfill Obsidian's Node.doc / Node.win augmentation so plugin code that
+// reads `element.doc` / `element.win` works under jsdom.
+if (typeof Node !== "undefined" && !Object.prototype.hasOwnProperty.call(Node.prototype, "doc")) {
+  Object.defineProperty(Node.prototype, "doc", {
+    get() {
+      return this.ownerDocument ?? global.document;
+    },
+    configurable: true,
+  });
+}
+if (typeof Node !== "undefined" && !Object.prototype.hasOwnProperty.call(Node.prototype, "win")) {
+  Object.defineProperty(Node.prototype, "win", {
+    get() {
+      return this.ownerDocument?.defaultView ?? global.window;
+    },
+    configurable: true,
+  });
+}
diff --git a/src/commands/CustomCommandChatModal.tsx b/src/commands/CustomCommandChatModal.tsx
index eab425f9..2f4346c7 100644
--- a/src/commands/CustomCommandChatModal.tsx
+++ b/src/commands/CustomCommandChatModal.tsx
@@ -504,7 +504,7 @@ export class CustomCommandChatModal {
    * the modal is positioned relative to the correct window.
    */
   private resolveWindow(view?: MarkdownView | null): Window {
-    return view?.containerEl?.ownerDocument?.defaultView ?? window;
+    return view?.containerEl?.win ?? window;
   }
 
   /**
@@ -513,7 +513,7 @@ export class CustomCommandChatModal {
    * appended to the document that owns the triggering view.
    */
   private resolveDocument(view?: MarkdownView | null): Document {
-    return view?.containerEl?.ownerDocument ?? document;
+    return view?.containerEl?.doc ?? activeDocument;
   }
 
   /**
diff --git a/src/components/CopilotView.tsx b/src/components/CopilotView.tsx
index d5ec8a60..6b655876 100644
--- a/src/components/CopilotView.tsx
+++ b/src/components/CopilotView.tsx
@@ -22,6 +22,7 @@ export default class CopilotView extends ItemView {
   private drawerHideObserver: MutationObserver | null = null;
   private layout: ChatViewLayout | null = null;
   private lastDrawerEl: HTMLElement | null = null;
+  private windowMigrationDestroy: (() => void) | null = null;
   eventTarget: EventTarget;
 
   constructor(
@@ -67,6 +68,19 @@ export default class CopilotView extends ItemView {
     this.setupMobileKeyboardObserver();
     this.setupDrawerHideObserver();
 
+    // Reason: When the leaf is dragged to (or back from) an Obsidian popout, the
+    // containerEl is reparented into a different window's document but onOpen
+    // does not re-fire. Lexical's editor._window stays bound to the original
+    // window, so input events fired in the popout never reach the editor.
+    // Tearing down and recreating the React root forces Lexical to re-register
+    // its root element under the new window — typing works again.
+    this.windowMigrationDestroy = this.containerEl.onWindowMigrated(() => {
+      if (!this.root) return;
+      this.root.unmount();
+      this.root = createRoot(this.containerEl.children[1]);
+      this.renderView(handleSaveAsNote, updateUserMessageHistory);
+    });
+
     // Reason: The view can move between containers (e.g. editor tab → drawer)
     // without onOpen firing again. Re-bind the drawer observer on layout changes
     // so it always watches the correct drawer element.
@@ -109,13 +123,13 @@ export default class CopilotView extends ItemView {
       // querying by data-type which is more brittle across Obsidian versions.
       const isCopilotActive = !!this.containerEl.closest(".workspace-drawer-active-tab-content");
       const kbHeight = parseFloat(
-        document.documentElement.style.getPropertyValue("--keyboard-height") || "0"
+        this.containerEl.doc.documentElement.style.getPropertyValue("--keyboard-height") || "0"
       );
       drawer.classList.toggle("copilot-keyboard-open", isCopilotActive && kbHeight > 0);
     };
 
     this.keyboardObserver = new MutationObserver(syncKeyboardClass);
-    this.keyboardObserver.observe(document.documentElement, {
+    this.keyboardObserver.observe(this.containerEl.doc.documentElement, {
       attributes: true,
       attributeFilter: ["style"],
     });
@@ -209,6 +223,8 @@ export default class CopilotView extends ItemView {
     this.keyboardObserver = null;
     this.drawerHideObserver?.disconnect();
     this.drawerHideObserver = null;
+    this.windowMigrationDestroy?.();
+    this.windowMigrationDestroy = null;
     this.layout?.destroy();
     this.layout = null;
     // Reason: Clean up the class on the tracked drawer element when the view is closed.
diff --git a/src/components/chat-components/ChatInput.tsx b/src/components/chat-components/ChatInput.tsx
index 7d3d7fe4..53ac2dd1 100644
--- a/src/components/chat-components/ChatInput.tsx
+++ b/src/components/chat-components/ChatInput.tsx
@@ -7,7 +7,6 @@ import {
   useProjectLoading,
 } from "@/aiParams";
 import { ChainType } from "@/chainFactory";
-import { AddImageModal } from "@/components/modals/AddImageModal";
 import { Button } from "@/components/ui/button";
 import { ModelSelector } from "@/components/ui/ModelSelector";
 import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from "@/components/ui/tooltip";
@@ -654,8 +653,10 @@ const ChatInput: React.FC<ChatInputProps> = ({
       }
     };
 
-    document.addEventListener("keydown", handleKeyDown);
-    return () => document.removeEventListener("keydown", handleKeyDown);
+    const doc = containerRef.current?.doc;
+    if (!doc) return;
+    doc.addEventListener("keydown", handleKeyDown);
+    return () => doc.removeEventListener("keydown", handleKeyDown);
   }, [editMode, onEditCancel]);
 
   // Handle tool button toggle-off events - remove corresponding pills
@@ -853,8 +854,17 @@ const ChatInput: React.FC<ChatInputProps> = ({
                       variant="ghost2"
                       size="fit"
                       className="tw-text-muted hover:tw-text-accent"
-                      onClick={() => {
-                        new AddImageModal(app, onAddImage).open();
+                      onClick={(e) => {
+                        const input = e.currentTarget.doc.createElement("input");
+                        input.type = "file";
+                        input.accept = "image/*";
+                        input.multiple = true;
+                        input.addEventListener(
+                          "change",
+                          () => onAddImage(Array.from(input.files || [])),
+                          { once: true }
+                        );
+                        input.click();
                       }}
                     >
                       <Image className="tw-size-4" />
diff --git a/src/components/chat-components/ChatSingleMessage.test.tsx b/src/components/chat-components/ChatSingleMessage.test.tsx
index 7bf06c07..473e6692 100644
--- a/src/components/chat-components/ChatSingleMessage.test.tsx
+++ b/src/components/chat-components/ChatSingleMessage.test.tsx
@@ -97,7 +97,7 @@ describe("think block rendering — closing tags are not consumed by indented co
   });
 
   beforeAll(() => {
-    (globalThis as any).activeDocument = document;
+    (window as any).activeDocument = window.document;
   });
 
   /**
@@ -204,7 +204,7 @@ describe("normalizeFootnoteRendering", () => {
   });
 
   it("removes separator and backref while preserving non-footnote elements", () => {
-    const container = document.createElement("div");
+    const container = window.document.createElement("div");
     container.innerHTML = `
       <div>
         <p>Body <sup><a href="#fn-1">1-1</a></sup></p>
@@ -229,7 +229,7 @@ describe("normalizeFootnoteRendering", () => {
   });
 
   it("leaves non-numeric footnote references untouched", () => {
-    const container = document.createElement("div");
+    const container = window.document.createElement("div");
     container.innerHTML = `
       <p>Body <sup><a href="#fn-note">Note-A</a></sup></p>
       <a class="footnote-backref" href="#ref">↩</a>
@@ -269,7 +269,7 @@ describe("ChatSingleMessage", () => {
   });
 
   beforeAll(() => {
-    (globalThis as any).activeDocument = document;
+    (window as any).activeDocument = window.document;
   });
 
   it("normalizes rendered footnotes for assistant messages", async () => {
diff --git a/src/components/chat-components/ChatSingleMessage.tsx b/src/components/chat-components/ChatSingleMessage.tsx
index 2f7a08df..e9ba7a7a 100644
--- a/src/components/chat-components/ChatSingleMessage.tsx
+++ b/src/components/chat-components/ChatSingleMessage.tsx
@@ -116,10 +116,15 @@ export const linkInlineCitations = (root: HTMLElement): void => {
 
   if (citationAnchors.size === 0) return;
 
+  // Bind DOM ops to the document that owns `root` — the chat message may live
+  // in an Obsidian popout while a different window is focused, in which case
+  // `activeDocument` would create nodes with the wrong owner.
+  const doc = root.doc;
+
   // Collect text nodes that contain citation patterns (outside sources section)
   const sourcesEl = root.querySelector(".copilot-sources");
   const textNodes: Text[] = [];
-  const walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT, {
+  const walker = doc.createTreeWalker(root, NodeFilter.SHOW_TEXT, {
     acceptNode(node) {
       if (sourcesEl?.contains(node)) return NodeFilter.FILTER_REJECT;
       if (node.parentElement?.closest("code, pre")) return NodeFilter.FILTER_REJECT;
@@ -140,27 +145,27 @@ export const linkInlineCitations = (root: HTMLElement): void => {
     const text = node.textContent || "";
     INLINE_CITATION_RE.lastIndex = 0;
 
-    const fragment = document.createDocumentFragment();
+    const fragment = doc.createDocumentFragment();
     let lastIndex = 0;
     let match: RegExpExecArray | null;
 
     while ((match = INLINE_CITATION_RE.exec(text)) !== null) {
       // Text before the citation
       if (match.index > lastIndex) {
-        fragment.appendChild(document.createTextNode(text.slice(lastIndex, match.index)));
+        fragment.appendChild(doc.createTextNode(text.slice(lastIndex, match.index)));
       }
 
       const nums = match[1].split(/\s*,\s*/).map((s) => parseInt(s.trim(), 10));
       const allResolved = nums.every((num) => citationAnchors.has(num));
 
       if (allResolved) {
-        const span = document.createElement("span");
+        const span = doc.createElement("span");
         span.className = "copilot-citation-group";
-        span.appendChild(document.createTextNode("["));
+        span.appendChild(doc.createTextNode("["));
         nums.forEach((num, i) => {
-          if (i > 0) span.appendChild(document.createTextNode(", "));
+          if (i > 0) span.appendChild(doc.createTextNode(", "));
           const sourceAnchor = citationAnchors.get(num)!;
-          const link = document.createElement("a");
+          const link = doc.createElement("a");
           // Copy all attributes from the source anchor so Obsidian internal-link
           // metadata (e.g. data-href, class="internal-link") is preserved.
           for (const attr of Array.from(sourceAnchor.attributes)) {
@@ -172,17 +177,17 @@ export const linkInlineCitations = (root: HTMLElement): void => {
           link.setAttribute("aria-label", `Source ${num}`);
           span.appendChild(link);
         });
-        span.appendChild(document.createTextNode("]"));
+        span.appendChild(doc.createTextNode("]"));
         fragment.appendChild(span);
       } else {
-        fragment.appendChild(document.createTextNode(match[0]));
+        fragment.appendChild(doc.createTextNode(match[0]));
       }
 
       lastIndex = match.index + match[0].length;
     }
 
     if (lastIndex < text.length) {
-      fragment.appendChild(document.createTextNode(text.slice(lastIndex)));
+      fragment.appendChild(doc.createTextNode(text.slice(lastIndex)));
     }
 
     // If the text node is inside a placeholder span, replace the span itself
@@ -668,6 +673,9 @@ const ChatSingleMessage: React.FC<ChatSingleMessageProps> = ({
       const parsedMessage = parseToolCallMarkers(processedMessage, messageId.current);
 
       if (!isUnmountingRef.current) {
+        // Bind DOM ops to the document that owns the message container so
+        // popout-window chats don't pick up the wrong document if focus shifts.
+        const doc = contentRef.current.doc;
         // Track existing tool call and error block IDs
         const existingToolCallIds = new Set<string>();
         const existingErrorIds = new Set<string>();
@@ -695,7 +703,7 @@ const ChatSingleMessage: React.FC<ChatSingleMessageProps> = ({
             // Find where to insert this text segment
             const insertBefore = contentRef.current!.children[currentIndex];
 
-            const textDiv = document.createElement("div");
+            const textDiv = doc.createElement("div");
             textDiv.className = "message-segment";
 
             if (insertBefore) {
@@ -715,11 +723,11 @@ const ChatSingleMessage: React.FC<ChatSingleMessageProps> = ({
             currentIndex++;
           } else if (segment.type === "toolCall" && segment.toolCall) {
             const toolCallId = segment.toolCall.id;
-            let container = document.getElementById(`tool-call-${toolCallId}`);
+            let container = doc.getElementById(`tool-call-${toolCallId}`);
 
             if (!container) {
               const insertBefore = contentRef.current!.children[currentIndex];
-              const toolDiv = document.createElement("div");
+              const toolDiv = doc.createElement("div");
               toolDiv.className = "tool-call-container";
               toolDiv.id = `tool-call-${toolCallId}`;
 
@@ -747,12 +755,12 @@ const ChatSingleMessage: React.FC<ChatSingleMessageProps> = ({
             currentIndex++;
           } else if (segment.type === "error" && segment.error) {
             const errorId = segment.error.id;
-            let container = document.getElementById(`error-block-${errorId}`);
+            let container = doc.getElementById(`error-block-${errorId}`);
 
             if (!container) {
               // Insert error block at the current stream position
               const insertBefore = contentRef.current!.children[currentIndex];
-              const errorDiv = document.createElement("div");
+              const errorDiv = doc.createElement("div");
               errorDiv.className = "error-block-container";
               errorDiv.id = `error-block-${errorId}`;
 
@@ -791,7 +799,7 @@ const ChatSingleMessage: React.FC<ChatSingleMessageProps> = ({
 
         existingToolCallIds.forEach((id) => {
           if (!currentToolCallIds.has(id)) {
-            const element = document.getElementById(`tool-call-${id}`);
+            const element = doc.getElementById(`tool-call-${id}`);
             if (element) {
               removeToolCallRoot(messageId.current, rootsRef.current, id, "tool call removal");
               element.remove();
@@ -808,7 +816,7 @@ const ChatSingleMessage: React.FC<ChatSingleMessageProps> = ({
 
         existingErrorIds.forEach((id) => {
           if (!currentErrorIds.has(id)) {
-            const element = document.getElementById(`error-block-${id}`);
+            const element = doc.getElementById(`error-block-${id}`);
             if (element) {
               removeErrorBlockRoot(
                 messageId.current,
diff --git a/src/components/chat-components/ChatViewLayout.ts b/src/components/chat-components/ChatViewLayout.ts
index ead84ff2..667d3ded 100644
--- a/src/components/chat-components/ChatViewLayout.ts
+++ b/src/components/chat-components/ChatViewLayout.ts
@@ -49,7 +49,7 @@ export class ChatViewLayout {
 
     const syncClearance = () => {
       // Re-query each time to avoid stale references after theme reloads.
-      const statusBar = document.querySelector<HTMLElement>(".status-bar");
+      const statusBar = this.containerEl.doc.querySelector<HTMLElement>(".status-bar");
       const viewContent = this.containerEl.querySelector<HTMLElement>(".view-content");
       if (!statusBar || !viewContent) return;
 
diff --git a/src/components/chat-components/TypeaheadMenuPortal.tsx b/src/components/chat-components/TypeaheadMenuPortal.tsx
index 1251de24..fc21bdad 100644
--- a/src/components/chat-components/TypeaheadMenuPortal.tsx
+++ b/src/components/chat-components/TypeaheadMenuPortal.tsx
@@ -60,30 +60,36 @@ export function TypeaheadMenuPortal({
     null
   );
 
-  // Calculate dynamic width based on content
-  const calculateWidth = useCallback(() => {
-    const maxAllowedWidth = Math.floor(window.innerWidth * MAX_WIDTH_PERCENTAGE);
+  // Derive the popout-aware window/document from the range itself so positioning
+  // and the portal target follow the chat's window, not whichever happens to be focused.
+  const targetWin: Window = range?.startContainer.win ?? window;
 
-    if (options.length === 0) return Math.min(MENU_WIDTH, maxAllowedWidth);
+  const calculateWidth = useCallback(
+    (win: Window) => {
+      const maxAllowedWidth = Math.floor(win.innerWidth * MAX_WIDTH_PERCENTAGE);
 
-    const maxTitleLength = Math.max(...options.map((opt) => opt.title.length));
-    const maxSubtitleLength = Math.max(...options.map((opt) => opt.subtitle?.length || 0));
+      if (options.length === 0) return Math.min(MENU_WIDTH, maxAllowedWidth);
 
-    const estimatedWidth = Math.max(maxTitleLength * 8 + 32, maxSubtitleLength * 6 + 32);
-    const preferredWidth = Math.min(Math.max(estimatedWidth, 300), MENU_WIDTH);
+      const maxTitleLength = Math.max(...options.map((opt) => opt.title.length));
+      const maxSubtitleLength = Math.max(...options.map((opt) => opt.subtitle?.length || 0));
 
-    return Math.min(preferredWidth, maxAllowedWidth);
-  }, [options]);
+      const estimatedWidth = Math.max(maxTitleLength * 8 + 32, maxSubtitleLength * 6 + 32);
+      const preferredWidth = Math.min(Math.max(estimatedWidth, 300), MENU_WIDTH);
+
+      return Math.min(preferredWidth, maxAllowedWidth);
+    },
+    [options]
+  );
 
-  // Positioning for text-triggered menus
   const recalcPosition = useCallback(() => {
     if (!range) return;
+    const win = range.startContainer.win;
     const rect = range.getBoundingClientRect();
-    const containerWidth = calculateWidth();
+    const containerWidth = calculateWidth(win);
 
     const top = rect.top - 4;
     const minLeft = 8;
-    const maxLeft = window.innerWidth - containerWidth - 8;
+    const maxLeft = win.innerWidth - containerWidth - 8;
     const left = Math.min(Math.max(rect.left, minLeft), maxLeft);
 
     setPosition({
@@ -98,14 +104,16 @@ export function TypeaheadMenuPortal({
   }, [recalcPosition]);
 
   useEffect(() => {
+    if (!range) return;
+    const win = range.startContainer.win;
     const handler = () => recalcPosition();
-    window.addEventListener("resize", handler);
-    document.addEventListener("scroll", handler, { passive: true });
+    win.addEventListener("resize", handler);
+    win.document.addEventListener("scroll", handler, { passive: true });
     return () => {
-      window.removeEventListener("resize", handler);
-      document.removeEventListener("scroll", handler);
+      win.removeEventListener("resize", handler);
+      win.document.removeEventListener("scroll", handler);
     };
-  }, [recalcPosition]);
+  }, [recalcPosition, range]);
 
   if (!position || options.length === 0) {
     return null;
@@ -135,7 +143,7 @@ export function TypeaheadMenuPortal({
     </div>
   );
 
-  return createPortal(container, document.body);
+  return createPortal(container, targetWin.document.body);
 }
 
 export { tryToPositionRange };
diff --git a/src/components/chat-components/pills/ActiveNotePillNode.tsx b/src/components/chat-components/pills/ActiveNotePillNode.tsx
index c7e2a059..421416a0 100644
--- a/src/components/chat-components/pills/ActiveNotePillNode.tsx
+++ b/src/components/chat-components/pills/ActiveNotePillNode.tsx
@@ -4,11 +4,12 @@ import {
   DOMConversionOutput,
   DOMExportOutput,
   EditorConfig,
+  LexicalEditor,
   LexicalNode,
   NodeKey,
   $getRoot,
 } from "lexical";
-import { BasePillNode, SerializedBasePillNode } from "./BasePillNode";
+import { BasePillNode, getEditorDocument, SerializedBasePillNode } from "./BasePillNode";
 import { TruncatedPillText } from "./TruncatedPillText";
 import { PillBadge } from "./PillBadge";
 import { useActiveFile } from "../context/ActiveFileContext";
@@ -43,8 +44,8 @@ export class ActiveNotePillNode extends BasePillNode {
     return "data-lexical-active-note-pill";
   }
 
-  createDOM(_config: EditorConfig): HTMLElement {
-    const span = document.createElement("span");
+  createDOM(_config: EditorConfig, editor: LexicalEditor): HTMLElement {
+    const span = getEditorDocument(editor).createElement("span");
     span.className = "active-note-pill-wrapper";
     return span;
   }
@@ -75,8 +76,8 @@ export class ActiveNotePillNode extends BasePillNode {
     };
   }
 
-  exportDOM(): DOMExportOutput {
-    const element = document.createElement("span");
+  exportDOM(editor: LexicalEditor): DOMExportOutput {
+    const element = getEditorDocument(editor).createElement("span");
     element.setAttribute("data-lexical-active-note-pill", "true");
     element.textContent = "{activeNote}";
     return { element };
diff --git a/src/components/chat-components/pills/ActiveWebTabPillNode.tsx b/src/components/chat-components/pills/ActiveWebTabPillNode.tsx
index a7c06ff8..802019d2 100644
--- a/src/components/chat-components/pills/ActiveWebTabPillNode.tsx
+++ b/src/components/chat-components/pills/ActiveWebTabPillNode.tsx
@@ -4,6 +4,7 @@ import {
   DOMConversionOutput,
   DOMExportOutput,
   EditorConfig,
+  LexicalEditor,
   LexicalNode,
   NodeKey,
   $getRoot,
@@ -11,7 +12,7 @@ import {
 import { Globe } from "lucide-react";
 import { Platform } from "obsidian";
 import { ACTIVE_WEB_TAB_MARKER } from "@/constants";
-import { BasePillNode, SerializedBasePillNode } from "./BasePillNode";
+import { BasePillNode, getEditorDocument, SerializedBasePillNode } from "./BasePillNode";
 import { TruncatedPillText } from "./TruncatedPillText";
 import { PillBadge } from "./PillBadge";
 import { useActiveWebTabState } from "../hooks/useActiveWebTabState";
@@ -44,8 +45,8 @@ export class ActiveWebTabPillNode extends BasePillNode {
     return "data-lexical-active-web-tab-pill";
   }
 
-  createDOM(_config: EditorConfig): HTMLElement {
-    const span = document.createElement("span");
+  createDOM(_config: EditorConfig, editor: LexicalEditor): HTMLElement {
+    const span = getEditorDocument(editor).createElement("span");
     span.className = "active-web-tab-pill-wrapper";
     return span;
   }
@@ -76,8 +77,8 @@ export class ActiveWebTabPillNode extends BasePillNode {
     };
   }
 
-  exportDOM(): DOMExportOutput {
-    const element = document.createElement("span");
+  exportDOM(editor: LexicalEditor): DOMExportOutput {
+    const element = getEditorDocument(editor).createElement("span");
     element.setAttribute("data-lexical-active-web-tab-pill", "true");
     element.textContent = ACTIVE_WEB_TAB_MARKER;
     return { element };
diff --git a/src/components/chat-components/pills/BasePillNode.tsx b/src/components/chat-components/pills/BasePillNode.tsx
index 8a2dd5af..0e989103 100644
--- a/src/components/chat-components/pills/BasePillNode.tsx
+++ b/src/components/chat-components/pills/BasePillNode.tsx
@@ -3,12 +3,23 @@ import {
   DecoratorNode,
   DOMExportOutput,
   EditorConfig,
+  LexicalEditor,
   NodeKey,
   SerializedLexicalNode,
 } from "lexical";
 import { IPillNode } from "../plugins/PillDeletionPlugin";
 import { PillBadge } from "./PillBadge";
 
+/**
+ * Returns the Document that owns the given Lexical editor's root element.
+ * Pills must create DOM in the editor's window — using `activeDocument`
+ * (focused window) can produce nodes with the wrong owner when the chat is
+ * in an Obsidian popout but a different window is focused.
+ */
+export function getEditorDocument(editor: LexicalEditor): Document {
+  return editor.getRootElement()?.doc ?? activeDocument;
+}
+
 export interface SerializedBasePillNode extends SerializedLexicalNode {
   value: string;
 }
@@ -106,8 +117,8 @@ export abstract class BasePillNode extends DecoratorNode<JSX.Element> implements
   /**
    * Default DOM creation - subclasses can override for custom elements.
    */
-  createDOM(_config: EditorConfig): HTMLElement {
-    const span = document.createElement("span");
+  createDOM(_config: EditorConfig, editor: LexicalEditor): HTMLElement {
+    const span = getEditorDocument(editor).createElement("span");
     span.className = this.getClassName();
     return span;
   }
@@ -115,8 +126,8 @@ export abstract class BasePillNode extends DecoratorNode<JSX.Element> implements
   /**
    * Default DOM export - subclasses can override for custom attributes.
    */
-  exportDOM(): DOMExportOutput {
-    const element = document.createElement("span");
+  exportDOM(editor: LexicalEditor): DOMExportOutput {
+    const element = getEditorDocument(editor).createElement("span");
     element.setAttribute(this.getDataAttribute(), "");
     element.setAttribute("data-pill-value", this.__value);
     element.textContent = this.__value;
diff --git a/src/components/chat-components/pills/FolderPillNode.tsx b/src/components/chat-components/pills/FolderPillNode.tsx
index b90d7186..1c01605b 100644
--- a/src/components/chat-components/pills/FolderPillNode.tsx
+++ b/src/components/chat-components/pills/FolderPillNode.tsx
@@ -4,10 +4,11 @@ import {
   DOMConversionMap,
   DOMConversionOutput,
   DOMExportOutput,
+  LexicalEditor,
   LexicalNode,
   NodeKey,
 } from "lexical";
-import { BasePillNode, SerializedBasePillNode } from "./BasePillNode";
+import { BasePillNode, getEditorDocument, SerializedBasePillNode } from "./BasePillNode";
 import { TruncatedPillText } from "./TruncatedPillText";
 import { PillBadge } from "./PillBadge";
 
@@ -93,8 +94,8 @@ export class FolderPillNode extends BasePillNode {
   /**
    * Override to export DOM with curly braces
    */
-  exportDOM(): DOMExportOutput {
-    const element = document.createElement("span");
+  exportDOM(editor: LexicalEditor): DOMExportOutput {
+    const element = getEditorDocument(editor).createElement("span");
     element.setAttribute(this.getDataAttribute(), "");
     element.setAttribute("data-pill-value", this.__value);
     element.textContent = `{${this.getFolderPath()}}`;
diff --git a/src/components/chat-components/pills/NotePillNode.tsx b/src/components/chat-components/pills/NotePillNode.tsx
index a797ecf7..e98f3952 100644
--- a/src/components/chat-components/pills/NotePillNode.tsx
+++ b/src/components/chat-components/pills/NotePillNode.tsx
@@ -5,10 +5,11 @@ import {
   DOMConversionOutput,
   DOMExportOutput,
   EditorConfig,
+  LexicalEditor,
   LexicalNode,
   NodeKey,
 } from "lexical";
-import { BasePillNode, SerializedBasePillNode } from "./BasePillNode";
+import { BasePillNode, getEditorDocument, SerializedBasePillNode } from "./BasePillNode";
 import { TruncatedPillText } from "./TruncatedPillText";
 import { PillBadge } from "./PillBadge";
 
@@ -43,8 +44,8 @@ export class NotePillNode extends BasePillNode {
     return "data-lexical-note-pill";
   }
 
-  createDOM(_config: EditorConfig): HTMLElement {
-    const span = document.createElement("span");
+  createDOM(_config: EditorConfig, editor: LexicalEditor): HTMLElement {
+    const span = getEditorDocument(editor).createElement("span");
     span.className = "note-pill-wrapper";
     return span;
   }
@@ -78,8 +79,8 @@ export class NotePillNode extends BasePillNode {
     };
   }
 
-  exportDOM(): DOMExportOutput {
-    const element = document.createElement("span");
+  exportDOM(editor: LexicalEditor): DOMExportOutput {
+    const element = getEditorDocument(editor).createElement("span");
     element.setAttribute("data-lexical-note-pill", "true");
     element.setAttribute("data-note-title", this.__noteTitle);
     element.setAttribute("data-note-path", this.__notePath);
diff --git a/src/components/chat-components/pills/URLPillNode.tsx b/src/components/chat-components/pills/URLPillNode.tsx
index d93189f7..6bf3e8e5 100644
--- a/src/components/chat-components/pills/URLPillNode.tsx
+++ b/src/components/chat-components/pills/URLPillNode.tsx
@@ -5,10 +5,11 @@ import {
   DOMConversionOutput,
   DOMExportOutput,
   EditorConfig,
+  LexicalEditor,
   LexicalNode,
   NodeKey,
 } from "lexical";
-import { BasePillNode, SerializedBasePillNode } from "./BasePillNode";
+import { BasePillNode, getEditorDocument, SerializedBasePillNode } from "./BasePillNode";
 import { PillBadge } from "./PillBadge";
 
 export interface SerializedURLPillNode extends SerializedBasePillNode {
@@ -49,8 +50,8 @@ export class URLPillNode extends BasePillNode {
     return "data-lexical-url-pill";
   }
 
-  createDOM(_config: EditorConfig): HTMLElement {
-    const span = document.createElement("span");
+  createDOM(_config: EditorConfig, editor: LexicalEditor): HTMLElement {
+    const span = getEditorDocument(editor).createElement("span");
     span.className = "url-pill-wrapper";
     return span;
   }
@@ -85,8 +86,8 @@ export class URLPillNode extends BasePillNode {
     };
   }
 
-  exportDOM(): DOMExportOutput {
-    const element = document.createElement("span");
+  exportDOM(editor: LexicalEditor): DOMExportOutput {
+    const element = getEditorDocument(editor).createElement("span");
     element.setAttribute("data-lexical-url-pill", "true");
     element.setAttribute("data-url", this.__url);
     if (this.__title) {
diff --git a/src/components/chat-components/pills/WebTabPillNode.tsx b/src/components/chat-components/pills/WebTabPillNode.tsx
index 95cceb0e..9a9f2ff2 100644
--- a/src/components/chat-components/pills/WebTabPillNode.tsx
+++ b/src/components/chat-components/pills/WebTabPillNode.tsx
@@ -5,12 +5,13 @@ import {
   DOMConversionOutput,
   DOMExportOutput,
   EditorConfig,
+  LexicalEditor,
   LexicalNode,
   NodeKey,
 } from "lexical";
 import { Globe } from "lucide-react";
 import { getDomainFromUrl } from "@/utils";
-import { BasePillNode, SerializedBasePillNode } from "./BasePillNode";
+import { BasePillNode, getEditorDocument, SerializedBasePillNode } from "./BasePillNode";
 import { PillBadge } from "./PillBadge";
 
 export interface SerializedWebTabPillNode extends SerializedBasePillNode {
@@ -63,8 +64,8 @@ export class WebTabPillNode extends BasePillNode {
     return "data-lexical-web-tab-pill";
   }
 
-  createDOM(_config: EditorConfig): HTMLElement {
-    const span = document.createElement("span");
+  createDOM(_config: EditorConfig, editor: LexicalEditor): HTMLElement {
+    const span = getEditorDocument(editor).createElement("span");
     span.className = "web-tab-pill-wrapper";
     return span;
   }
@@ -99,8 +100,8 @@ export class WebTabPillNode extends BasePillNode {
     };
   }
 
-  exportDOM(): DOMExportOutput {
-    const element = document.createElement("span");
+  exportDOM(editor: LexicalEditor): DOMExportOutput {
+    const element = getEditorDocument(editor).createElement("span");
     element.setAttribute("data-lexical-web-tab-pill", "true");
     element.setAttribute("data-url", this.__url);
     if (this.__title) {
diff --git a/src/components/command-ui/draggable-modal.tsx b/src/components/command-ui/draggable-modal.tsx
index 012b55bc..82372066 100644
--- a/src/components/command-ui/draggable-modal.tsx
+++ b/src/components/command-ui/draggable-modal.tsx
@@ -80,7 +80,7 @@ export function DraggableModal({
   // so a click on the drag handle (without dragging) preserves anchorBottom behavior.
   const handleMouseDown = useCallback(
     (e: React.MouseEvent) => {
-      const ownerDoc = e.currentTarget.ownerDocument;
+      const ownerDoc = (e.currentTarget as HTMLElement).doc;
       const startX = e.clientX;
       const startY = e.clientY;
 
@@ -189,7 +189,7 @@ export function DraggableModal({
     if (anchorBottom !== undefined || isManualPositionRef.current) return;
     if (heightPx === null) return;
 
-    const ownerWindow = dragRef.current?.ownerDocument?.defaultView ?? window;
+    const ownerWindow = dragRef.current?.win ?? window;
     const maxY = ownerWindow.innerHeight - 12 - heightPx;
     const newY = Math.max(12, Math.min(position.y, maxY));
     if (Math.abs(position.y - newY) < 1) return;
@@ -233,7 +233,7 @@ export function DraggableModal({
   useEffect(() => {
     if (!open) return;
 
-    const ownerDocument = dragRef.current?.ownerDocument ?? document;
+    const ownerDocument = dragRef.current?.doc ?? activeDocument;
 
     const handleKeyDown = (e: KeyboardEvent) => {
       // Respect defaultPrevented to let internal components (e.g., Lexical typeahead, Radix menus) consume Escape first
diff --git a/src/components/command-ui/markdown-preview.tsx b/src/components/command-ui/markdown-preview.tsx
index 10f8a962..9e9fa329 100644
--- a/src/components/command-ui/markdown-preview.tsx
+++ b/src/components/command-ui/markdown-preview.tsx
@@ -24,8 +24,8 @@ export function MarkdownPreview({ content, renderMarkdown, className }: Markdown
     const currentGen = ++renderGenRef.current;
     // Reason: Render into a detached element so that if content changes
     // mid-render, the stale result never touches the live DOM.
-    // Reason: Use ownerDocument for popout-window safety in Obsidian
-    const scratchEl = targetEl.ownerDocument.createElement("div");
+    // Reason: Use the target's doc for popout-window safety in Obsidian
+    const scratchEl = targetEl.doc.createElement("div");
 
     targetEl.innerHTML = "";
     renderMarkdown(content, scratchEl)
diff --git a/src/components/command-ui/menu-command-modal.tsx b/src/components/command-ui/menu-command-modal.tsx
index 358edb51..98c93df8 100644
--- a/src/components/command-ui/menu-command-modal.tsx
+++ b/src/components/command-ui/menu-command-modal.tsx
@@ -117,7 +117,7 @@ export function MenuCommandModal({
     if (!open) return;
 
     const modalEl = innerRef.current?.closest<HTMLElement>('[data-copilot-draggable-modal="true"]');
-    const ownerDocument = modalEl?.ownerDocument ?? document;
+    const ownerDocument = modalEl?.doc ?? activeDocument;
 
     const handleKeyDown = (e: KeyboardEvent) => {
       // Only handle when result is ready and not busy
diff --git a/src/components/modals/AddImageModal.tsx b/src/components/modals/AddImageModal.tsx
deleted file mode 100644
index 4c3b6224..00000000
--- a/src/components/modals/AddImageModal.tsx
+++ /dev/null
@@ -1,29 +0,0 @@
-import { App } from "obsidian";
-
-export class AddImageModal {
-  private app: App;
-  private onImagesSelected: (files: File[]) => void;
-
-  constructor(app: App, onImagesSelected: (files: File[]) => void) {
-    this.app = app;
-    this.onImagesSelected = onImagesSelected;
-  }
-
-  open() {
-    const input = document.createElement("input");
-    input.type = "file";
-    input.accept = "image/*";
-    input.multiple = true;
-    input.style.display = "none";
-
-    input.addEventListener("change", () => {
-      const files = Array.from(input.files || []);
-      this.onImagesSelected(files);
-      // Clean up
-      document.body.removeChild(input);
-    });
-
-    document.body.appendChild(input);
-    input.click();
-  }
-}
diff --git a/src/components/modals/SourcesModal.tsx b/src/components/modals/SourcesModal.tsx
index 4087bb88..1792dad8 100644
--- a/src/components/modals/SourcesModal.tsx
+++ b/src/components/modals/SourcesModal.tsx
@@ -79,7 +79,7 @@ export class SourcesModal extends Modal {
       // Display with 4 decimals to match SearchCore logs and avoid apparent ties
       if (typeof source.score === "number") {
         itemContainer.appendChild(
-          document.createTextNode(` - Relevance score: ${source.score.toFixed(4)}`)
+          this.contentEl.doc.createTextNode(` - Relevance score: ${source.score.toFixed(4)}`)
         );
       }
 
diff --git a/src/components/quick-ask/QuickAskOverlay.tsx b/src/components/quick-ask/QuickAskOverlay.tsx
index 6ba388b8..c21f058a 100644
--- a/src/components/quick-ask/QuickAskOverlay.tsx
+++ b/src/components/quick-ask/QuickAskOverlay.tsx
@@ -314,7 +314,7 @@ export class QuickAskOverlay {
 
     if (QuickAskOverlay.overlayRoot) return QuickAskOverlay.overlayRoot;
 
-    const doc = host.ownerDocument ?? document;
+    const doc = host.doc;
     const root = doc.createElement("div");
     root.className = "copilot-quick-ask-overlay-root";
     host.appendChild(root);
@@ -325,11 +325,11 @@ export class QuickAskOverlay {
 
   private mountOverlay(): void {
     // Mount overlay inside editor DOM for proper layering
-    const overlayHost = this.options.view.dom ?? document.body;
+    const overlayHost = this.options.view.dom ?? activeDocument.body;
     this.overlayHost = overlayHost;
 
     // Capture owner document/window for popout window compatibility
-    const doc = overlayHost.ownerDocument ?? document;
+    const doc = overlayHost.doc;
     const win = doc.defaultView ?? window;
     this.ownerDocument = doc;
     this.ownerWindow = win;
@@ -384,7 +384,7 @@ export class QuickAskOverlay {
       if (event.key !== "Escape") return;
       if (event.defaultPrevented) return;
 
-      const doc = this.ownerDocument ?? document;
+      const doc = this.ownerDocument ?? activeDocument;
       const activeEl = doc.activeElement;
       const isFocusInsidePanel = !!(activeEl && this.overlayContainer?.contains(activeEl));
 
@@ -532,7 +532,7 @@ export class QuickAskOverlay {
       return;
     }
 
-    const doc = this.ownerDocument ?? document;
+    const doc = this.ownerDocument ?? activeDocument;
     const hostRect = this.overlayHost?.getBoundingClientRect() ?? doc.body.getBoundingClientRect();
 
     const viewportWidth = hostRect.width;
@@ -665,7 +665,7 @@ export class QuickAskOverlay {
     this.resizeStartRect = rect;
     this.resizeStartMouse = start;
 
-    const doc = this.ownerDocument ?? document;
+    const doc = this.ownerDocument ?? activeDocument;
     const body = doc.body;
 
     // Prevent text selection and set resize cursor on body during drag
@@ -721,7 +721,7 @@ export class QuickAskOverlay {
     // Only restore body styles if we actually started resizing
     // This prevents polluting body styles when destroy() is called without resize
     if (this.isResizing) {
-      const doc = this.ownerDocument ?? document;
+      const doc = this.ownerDocument ?? activeDocument;
       const body = doc.body;
       doc.removeEventListener("mousemove", this.handleResizeMove, true);
       doc.removeEventListener("mouseup", this.handleResizeEnd, true);
@@ -740,7 +740,7 @@ export class QuickAskOverlay {
   private applyResize(clientX: number, clientY: number): void {
     if (!this.resizeStartRect || !this.resizeStartMouse || !this.resizeDirection) return;
 
-    const doc = this.ownerDocument ?? document;
+    const doc = this.ownerDocument ?? activeDocument;
     const hostRect = this.overlayHost?.getBoundingClientRect() ?? doc.body.getBoundingClientRect();
 
     const deltaX = clientX - this.resizeStartMouse.x;
@@ -856,7 +856,7 @@ export class QuickAskOverlay {
   private updateDragPosition(): void {
     if (!this.overlayContainer || !this.dragPosition) return;
 
-    const doc = this.ownerDocument ?? document;
+    const doc = this.ownerDocument ?? activeDocument;
     const hostRect = this.overlayHost?.getBoundingClientRect() ?? doc.body.getBoundingClientRect();
 
     const viewportWidth = hostRect.width;
diff --git a/src/contexts/TabContext.tsx b/src/contexts/TabContext.tsx
index 1f0563d9..7527b5c2 100644
--- a/src/contexts/TabContext.tsx
+++ b/src/contexts/TabContext.tsx
@@ -15,7 +15,7 @@ export const TabProvider: React.FC<{ children: React.ReactNode }> = ({ children
 
   useEffect(() => {
     if (!hasInitialized.current) {
-      const modal = document.querySelector(".modal-container") as HTMLElement;
+      const modal = activeDocument.querySelector(".modal-container") as HTMLElement;
       setModalContainer(modal);
       hasInitialized.current = true;
     }
diff --git a/src/hooks/use-draggable.ts b/src/hooks/use-draggable.ts
index 85344e91..73e8ec0a 100644
--- a/src/hooks/use-draggable.ts
+++ b/src/hooks/use-draggable.ts
@@ -106,7 +106,7 @@ export function useDraggable(options: UseDraggableOptions = {}) {
       const el = dragRef.current;
 
       if (bounds === "window" && el) {
-        const ownerWindow = el.ownerDocument?.defaultView ?? window;
+        const ownerWindow = el.win;
         const rect = el.getBoundingClientRect();
         const maxX = ownerWindow.innerWidth - rect.width;
         const maxY = ownerWindow.innerHeight - rect.height;
@@ -141,7 +141,7 @@ export function useDraggable(options: UseDraggableOptions = {}) {
   const scheduleApply = useCallback((): void => {
     if (rafIdRef.current != null) return;
 
-    const ownerWindow = dragRef.current?.ownerDocument?.defaultView ?? window;
+    const ownerWindow = dragRef.current?.win ?? window;
     rafIdRef.current = ownerWindow.requestAnimationFrame(() => {
       rafIdRef.current = null;
 
@@ -192,7 +192,7 @@ export function useDraggable(options: UseDraggableOptions = {}) {
         y: e.clientY - current.y,
       };
 
-      const ownerDocument = dragRef.current?.ownerDocument ?? document;
+      const ownerDocument = dragRef.current?.doc ?? activeDocument;
       const ownerWindow = ownerDocument.defaultView ?? window;
       const body = ownerDocument.body;
       previousBodyStyleRef.current = {
diff --git a/src/hooks/use-resizable.ts b/src/hooks/use-resizable.ts
index 6d58f459..c06c0206 100644
--- a/src/hooks/use-resizable.ts
+++ b/src/hooks/use-resizable.ts
@@ -95,7 +95,7 @@ export function useRafResizable(options: UseRafResizableOptions): UseRafResizabl
 
         // Capture owner document/window from the event target
         const targetElement = e.currentTarget as HTMLElement | null;
-        const ownerDoc = targetElement?.ownerDocument ?? document;
+        const ownerDoc = targetElement?.doc ?? activeDocument;
         ownerDocumentRef.current = ownerDoc;
         ownerWindowRef.current = ownerDoc.defaultView ?? window;
 
@@ -133,7 +133,7 @@ export function useRafResizable(options: UseRafResizableOptions): UseRafResizabl
             ? "nesw-resize"
             : "nwse-resize";
 
-    const ownerDocument = ownerDocumentRef.current ?? document;
+    const ownerDocument = ownerDocumentRef.current ?? activeDocument;
     const ownerWindow = ownerWindowRef.current ?? window;
     const body = ownerDocument.body;
     const previousCursor = body.style.cursor;
diff --git a/src/integration_tests/AgentPrompt.test.ts b/src/integration_tests/AgentPrompt.test.ts
index 649d5391..fd0359e2 100644
--- a/src/integration_tests/AgentPrompt.test.ts
+++ b/src/integration_tests/AgentPrompt.test.ts
@@ -41,7 +41,7 @@ jest.mock("obsidian", () => ({
   })),
   Notice: jest.fn().mockImplementation(function (message) {
     this.message = message;
-    this.noticeEl = document.createElement("div");
+    this.noticeEl = window.document.createElement("div");
     this.hide = jest.fn();
   }),
   Platform: {
diff --git a/src/main.ts b/src/main.ts
index 0b7ab42e..b7c19aa2 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -91,6 +91,7 @@ export default class CopilotPlugin extends Plugin {
   chatSelectionHighlightController: ChatSelectionHighlightController;
   private selectionDebounceTimer?: number;
   private selectionChangeHandler?: () => void;
+  private selectionListenerDocument?: Document;
   private lastSelectionSignature?: string;
   private webSelectionTracker?: WebSelectionTracker;
   private readonly chatHistoryLastAccessedAtManager = new RecentUsageManager<string>();
@@ -378,8 +379,10 @@ export default class CopilotPlugin extends Plugin {
       }, 500);
     };
 
-    // Register the DOM selection change event
-    document.addEventListener("selectionchange", this.selectionChangeHandler);
+    // Capture the document at registration so removal targets the same one
+    // (activeDocument can change if the user focuses a popout window).
+    this.selectionListenerDocument = activeDocument;
+    this.selectionListenerDocument.addEventListener("selectionchange", this.selectionChangeHandler);
   }
 
   /**
@@ -389,9 +392,13 @@ export default class CopilotPlugin extends Plugin {
     if (this.selectionDebounceTimer) {
       window.clearTimeout(this.selectionDebounceTimer);
     }
-    if (this.selectionChangeHandler) {
-      document.removeEventListener("selectionchange", this.selectionChangeHandler);
+    if (this.selectionChangeHandler && this.selectionListenerDocument) {
+      this.selectionListenerDocument.removeEventListener(
+        "selectionchange",
+        this.selectionChangeHandler
+      );
     }
+    this.selectionListenerDocument = undefined;
   }
 
   /**