diff --git a/ui/src/components/DocumentAnnotationLayer.test.tsx b/ui/src/components/DocumentAnnotationLayer.test.tsx
index 80c6a010d9a..3c8296b7e1e 100644
--- a/ui/src/components/DocumentAnnotationLayer.test.tsx
+++ b/ui/src/components/DocumentAnnotationLayer.test.tsx
@@ -7,10 +7,12 @@ import { DocumentAnnotationLayer } from "./DocumentAnnotationLayer";
 const mockBuildAnchorFromContainerSelection = vi.hoisted(() => vi.fn());
 const mockGetContainerTextOffset = vi.hoisted(() => vi.fn());
 const mockRangesForNormalizedSpan = vi.hoisted(() => vi.fn());
+const mockIsCoarsePointerDevice = vi.hoisted(() => vi.fn(() => false));
 
 vi.mock("@/lib/document-annotation-selection", () => ({
   buildAnchorFromContainerSelection: mockBuildAnchorFromContainerSelection,
   getContainerTextOffset: mockGetContainerTextOffset,
+  isCoarsePointerDevice: mockIsCoarsePointerDevice,
   rangesForNormalizedSpan: mockRangesForNormalizedSpan,
 }));
 
@@ -54,6 +56,7 @@ describe("DocumentAnnotationLayer", () => {
     document.body.appendChild(container);
     mockRangesForNormalizedSpan.mockReturnValue([makeRange([makeRect(8, 12, 80, 18)])]);
     rectSpy = vi.spyOn(HTMLElement.prototype, "getBoundingClientRect").mockReturnValue(makeRect(0, 0, 400, 300));
+    mockIsCoarsePointerDevice.mockReturnValue(false);
   });
 
   afterEach(async () => {
@@ -297,4 +300,249 @@ describe("DocumentAnnotationLayer", () => {
     (globalThis as { CSS?: unknown }).CSS = originalCss;
     (globalThis as { Highlight?: unknown }).Highlight = originalHighlight;
   });
+
+  it("captures a coarse-pointer selection once after selectionchange settles", async () => {
+    mockIsCoarsePointerDevice.mockReturnValue(true);
+    const body = document.createElement("div");
+    const textNode = document.createTextNode("Select this text.");
+    body.appendChild(textNode);
+    const range = document.createRange();
+    range.setStart(textNode, 0);
+    range.setEnd(textNode, 6);
+    range.getBoundingClientRect = () => makeRect(12, 24, 64, 18);
+    vi.spyOn(window, "getSelection").mockReturnValue({
+      rangeCount: 1,
+      isCollapsed: false,
+      getRangeAt: () => range,
+    } as unknown as Selection);
+    mockGetContainerTextOffset.mockReturnValue({
+      startOffset: 0,
+      endOffset: 6,
+      containerText: "Select this text.",
+      selectedText: "Select",
+    });
+    mockBuildAnchorFromContainerSelection.mockReturnValue({
+      selector: {
+        quote: { exact: "Select", prefix: "", suffix: " this" },
+        position: { normalizedStart: 0, normalizedEnd: 6, markdownStart: 0, markdownEnd: 6 },
+      },
+    });
+    const onPendingAnchorChange = vi.fn();
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <DocumentAnnotationLayer
+          containerRef={{ current: body }}
+          markdown="Select this text."
+          threads={[]}
+          focusedThreadId={null}
+          onThreadFocus={vi.fn()}
+          pendingAnchor={null}
+          onPendingAnchorChange={onPendingAnchorChange}
+          onRequestComment={vi.fn()}
+        />,
+      );
+    });
+
+    document.dispatchEvent(new Event("selectionchange"));
+    document.dispatchEvent(new Event("selectionchange"));
+    document.dispatchEvent(new Event("selectionchange"));
+    await new Promise((resolve) => setTimeout(resolve, 250));
+
+    expect(mockGetContainerTextOffset).not.toHaveBeenCalled();
+    expect(mockBuildAnchorFromContainerSelection).not.toHaveBeenCalled();
+    expect(onPendingAnchorChange).not.toHaveBeenCalled();
+
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 180));
+    });
+
+    expect(mockGetContainerTextOffset).toHaveBeenCalledTimes(1);
+    expect(mockBuildAnchorFromContainerSelection).toHaveBeenCalledTimes(1);
+    expect(onPendingAnchorChange).toHaveBeenCalledTimes(1);
+  });
+
+  it("uses the short gesture-end delay and skips unchanged settled selections", async () => {
+    mockIsCoarsePointerDevice.mockReturnValue(true);
+    const body = document.createElement("div");
+    const textNode = document.createTextNode("Select this text.");
+    body.appendChild(textNode);
+    const range = document.createRange();
+    range.setStart(textNode, 0);
+    range.setEnd(textNode, 6);
+    range.getBoundingClientRect = () => makeRect(12, 24, 64, 18);
+    vi.spyOn(window, "getSelection").mockReturnValue({
+      rangeCount: 1,
+      isCollapsed: false,
+      getRangeAt: () => range,
+    } as unknown as Selection);
+    mockGetContainerTextOffset.mockReturnValue({
+      startOffset: 0,
+      endOffset: 6,
+      containerText: "Select this text.",
+      selectedText: "Select",
+    });
+    mockBuildAnchorFromContainerSelection.mockReturnValue({
+      selector: {
+        quote: { exact: "Select", prefix: "", suffix: " this" },
+        position: { normalizedStart: 0, normalizedEnd: 6, markdownStart: 0, markdownEnd: 6 },
+      },
+    });
+    const onPendingAnchorChange = vi.fn();
+    root = createRoot(container);
+
+    await act(async () => {
+      root?.render(
+        <DocumentAnnotationLayer
+          containerRef={{ current: body }}
+          markdown="Select this text."
+          threads={[]}
+          focusedThreadId={null}
+          onThreadFocus={vi.fn()}
+          pendingAnchor={null}
+          onPendingAnchorChange={onPendingAnchorChange}
+          onRequestComment={vi.fn()}
+        />,
+      );
+    });
+
+    document.dispatchEvent(new Event("selectionchange"));
+    document.dispatchEvent(new Event("pointerup"));
+    await new Promise((resolve) => setTimeout(resolve, 80));
+    expect(mockBuildAnchorFromContainerSelection).not.toHaveBeenCalled();
+
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 60));
+    });
+    expect(mockBuildAnchorFromContainerSelection).toHaveBeenCalledTimes(1);
+    expect(onPendingAnchorChange).toHaveBeenCalledTimes(1);
+
+    document.dispatchEvent(new Event("selectionchange"));
+    document.dispatchEvent(new Event("touchend"));
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 140));
+    });
+
+    expect(mockGetContainerTextOffset).toHaveBeenCalledTimes(1);
+    expect(mockBuildAnchorFromContainerSelection).toHaveBeenCalledTimes(1);
+    expect(onPendingAnchorChange).toHaveBeenCalledTimes(1);
+  });
+
+  it("places a near-top selection toolbar below the selection and within the viewport", async () => {
+    const body = document.createElement("div");
+    const textNode = document.createTextNode("Select this text.");
+    body.appendChild(textNode);
+    const range = document.createRange();
+    range.setStart(textNode, 0);
+    range.setEnd(textNode, 6);
+    range.getBoundingClientRect = () => makeRect(-40, 2, 40, 18);
+    vi.spyOn(window, "getSelection").mockReturnValue({
+      rangeCount: 1,
+      isCollapsed: false,
+      getRangeAt: () => range,
+    } as unknown as Selection);
+    mockGetContainerTextOffset.mockReturnValue({
+      startOffset: 0,
+      endOffset: 6,
+      containerText: "Select this text.",
+      selectedText: "Select",
+    });
+    mockBuildAnchorFromContainerSelection.mockReturnValue({
+      selector: {
+        quote: { exact: "Select", prefix: "", suffix: " this" },
+        position: { normalizedStart: 0, normalizedEnd: 6, markdownStart: 0, markdownEnd: 6 },
+      },
+    });
+    root = createRoot(container);
+    let capturedAnchor: React.ComponentProps<typeof DocumentAnnotationLayer>["pendingAnchor"] = null;
+    const renderLayer = () => (
+      <DocumentAnnotationLayer
+        containerRef={{ current: body }}
+        markdown="Select this text."
+        threads={[]}
+        focusedThreadId={null}
+        onThreadFocus={vi.fn()}
+        pendingAnchor={capturedAnchor}
+        onPendingAnchorChange={(anchor) => {
+          capturedAnchor = anchor;
+        }}
+        onRequestComment={vi.fn()}
+        testWindow={{ innerWidth: 320, innerHeight: 640 }}
+      />
+    );
+
+    await act(async () => {
+      root?.render(renderLayer());
+    });
+    await act(async () => {
+      document.dispatchEvent(new Event("selectionchange"));
+    });
+    await act(async () => {
+      root?.render(renderLayer());
+    });
+
+    const toolbar = container.querySelector<HTMLElement>('[data-testid="document-annotation-selection-toolbar"]');
+    expect(toolbar?.style.top).toBe("28px");
+    expect(toolbar?.style.left).toBe("8px");
+  });
+
+  it("uses the settled pending anchor for an explicit shortcut request", async () => {
+    const body = document.createElement("div");
+    const textNode = document.createTextNode("Select this text.");
+    body.appendChild(textNode);
+    const range = document.createRange();
+    range.setStart(textNode, 0);
+    range.setEnd(textNode, 6);
+    range.getBoundingClientRect = () => makeRect(12, 24, 64, 18);
+    vi.spyOn(window, "getSelection").mockReturnValue({
+      rangeCount: 1,
+      isCollapsed: false,
+      getRangeAt: () => range,
+    } as unknown as Selection);
+    mockGetContainerTextOffset.mockReturnValue({
+      startOffset: 0,
+      endOffset: 6,
+      containerText: "Select this text.",
+      selectedText: "Select",
+    });
+    mockBuildAnchorFromContainerSelection.mockReturnValue({
+      selector: {
+        quote: { exact: "Select", prefix: "", suffix: " this" },
+        position: { normalizedStart: 0, normalizedEnd: 6, markdownStart: 0, markdownEnd: 6 },
+      },
+    });
+    const onRequestComment = vi.fn();
+    let pendingAnchor: React.ComponentProps<typeof DocumentAnnotationLayer>["pendingAnchor"] = null;
+    root = createRoot(container);
+    const renderLayer = (captureSelectionRequestId: number) => (
+      <DocumentAnnotationLayer
+        containerRef={{ current: body }}
+        markdown="Select this text."
+        threads={[]}
+        focusedThreadId={null}
+        onThreadFocus={vi.fn()}
+        pendingAnchor={pendingAnchor}
+        onPendingAnchorChange={(anchor) => {
+          pendingAnchor = anchor;
+        }}
+        onRequestComment={onRequestComment}
+        captureSelectionRequestId={captureSelectionRequestId}
+      />
+    );
+
+    await act(async () => {
+      root?.render(renderLayer(0));
+    });
+    await act(async () => {
+      document.dispatchEvent(new Event("selectionchange"));
+    });
+    await act(async () => {
+      root?.render(renderLayer(1));
+    });
+
+    expect(mockBuildAnchorFromContainerSelection).toHaveBeenCalledTimes(1);
+    expect(onRequestComment).toHaveBeenCalledTimes(1);
+    expect(onRequestComment).toHaveBeenCalledWith(pendingAnchor);
+  });
 });
diff --git a/ui/src/components/DocumentAnnotationLayer.tsx b/ui/src/components/DocumentAnnotationLayer.tsx
index d9418aae7fe..b1077ace3a2 100644
--- a/ui/src/components/DocumentAnnotationLayer.tsx
+++ b/ui/src/components/DocumentAnnotationLayer.tsx
@@ -9,6 +9,7 @@ import { cn } from "@/lib/utils";
 import {
   buildAnchorFromContainerSelection,
   getContainerTextOffset,
+  isCoarsePointerDevice,
   rangesForNormalizedSpan,
 } from "@/lib/document-annotation-selection";
 import {
@@ -66,6 +67,11 @@ export interface AnnotationLayerProps {
 
 /** Synthetic thread id used to render the in-progress (pending) comment highlight. */
 const PENDING_HIGHLIGHT_THREAD_ID = "__paperclip-pending-annotation__";
+const COARSE_SELECTION_SETTLE_MS = 400;
+const COARSE_GESTURE_END_CAPTURE_MS = 120;
+const TOOLBAR_WIDTH = 160;
+const TOOLBAR_HEIGHT = 36;
+const TOOLBAR_VIEWPORT_GAP = 8;
 
 interface HighlightRect {
   threadId: string;
@@ -86,6 +92,14 @@ interface ToolbarPosition {
   left: number;
 }
 
+interface SelectionSnapshot {
+  startContainer: Node;
+  startOffset: number;
+  endContainer: Node;
+  endOffset: number;
+  selectedText: string;
+}
+
 type NativeHighlightKind = "open" | "focused" | "stale" | "resolved";
 
 type NativeHighlightRanges = Record<NativeHighlightKind, Range[]>;
@@ -241,12 +255,16 @@ export function DocumentAnnotationLayer({
   hideResolved = true,
   captureSelectionRequestId,
   pendingHighlightText = null,
+  testWindow,
 }: AnnotationLayerProps) {
   const [highlightRects, setHighlightRects] = useState<HighlightRect[]>([]);
   const [hoveredThreadId, setHoveredThreadId] = useState<string | null>(null);
   const [toolbarPosition, setToolbarPosition] = useState<ToolbarPosition | null>(null);
   const overlayRef = useRef<HTMLDivElement | null>(null);
   const lastCaptureSelectionRequestIdRef = useRef<number>(0);
+  const selectionCaptureTimeoutRef = useRef<number | null>(null);
+  const lastProcessedSelectionRef = useRef<SelectionSnapshot | null>(null);
+  const hasProcessedSelectionRef = useRef(false);
   const reactId = useId();
   const nativeHighlightInstanceId = useMemo(
     () => `document-annotation-${reactId.replace(/[^a-zA-Z0-9_-]/g, "")}`,
@@ -410,7 +428,7 @@ export function DocumentAnnotationLayer({
     };
   }, [computeHighlightRects, containerRef, selectionDebugEnabled]);
 
-  const captureSelection = useCallback((): PendingAnchor | null => {
+  const captureSelection = useCallback((): PendingAnchor | null | undefined => {
     const container = containerRef.current;
     const overlay = overlayRef.current;
     if (!container || !overlay) return null;
@@ -419,23 +437,88 @@ export function DocumentAnnotationLayer({
     const range = selection.getRangeAt(0);
     if (!container.contains(range.commonAncestorContainer)) return null;
     if (selectionTouchesEditableElement(container, range)) return null;
+    const snapshot: SelectionSnapshot = {
+      startContainer: range.startContainer,
+      startOffset: range.startOffset,
+      endContainer: range.endContainer,
+      endOffset: range.endOffset,
+      selectedText: range.toString(),
+    };
+    const previous = lastProcessedSelectionRef.current;
+    if (
+      previous
+      && previous.startContainer === snapshot.startContainer
+      && previous.startOffset === snapshot.startOffset
+      && previous.endContainer === snapshot.endContainer
+      && previous.endOffset === snapshot.endOffset
+      && previous.selectedText === snapshot.selectedText
+    ) {
+      return undefined;
+    }
+    lastProcessedSelectionRef.current = snapshot;
+    hasProcessedSelectionRef.current = true;
     const containerOffset = getContainerTextOffset(container, range);
     if (!containerOffset) return null;
     const anchor = buildAnchorFromContainerSelection({ markdown, containerOffset });
     if (!anchor) return null;
     const overlayRect = overlay.getBoundingClientRect();
     const rect = range.getBoundingClientRect();
-    const top = Math.max(0, rect.top - overlayRect.top - 36);
-    const left = Math.max(0, rect.left - overlayRect.left + rect.width / 2 - 80);
+    const visualViewport = window.visualViewport;
+    const viewportLeft = visualViewport?.offsetLeft ?? 0;
+    const viewportTop = visualViewport?.offsetTop ?? 0;
+    const viewportWidth = visualViewport?.width ?? testWindow?.innerWidth ?? window.innerWidth;
+    const viewportHeight = visualViewport?.height ?? testWindow?.innerHeight ?? window.innerHeight;
+    const preferredTop = rect.top - TOOLBAR_HEIGHT - TOOLBAR_VIEWPORT_GAP;
+    const viewportBottom = viewportTop + viewportHeight;
+    const screenTop = preferredTop < viewportTop + TOOLBAR_VIEWPORT_GAP
+      ? Math.min(rect.bottom + TOOLBAR_VIEWPORT_GAP, viewportBottom - TOOLBAR_HEIGHT - TOOLBAR_VIEWPORT_GAP)
+      : preferredTop;
+    const preferredLeft = rect.left + rect.width / 2 - TOOLBAR_WIDTH / 2;
+    const screenLeft = Math.min(
+      Math.max(preferredLeft, viewportLeft + TOOLBAR_VIEWPORT_GAP),
+      viewportLeft + viewportWidth - TOOLBAR_WIDTH - TOOLBAR_VIEWPORT_GAP,
+    );
+    const top = Math.max(0, screenTop - overlayRect.top);
+    const left = Math.max(0, screenLeft - overlayRect.left);
     setToolbarPosition({ top, left });
     return {
       selector: anchor.selector,
       selectedText: containerOffset.selectedText,
     };
-  }, [containerRef, markdown]);
+  }, [containerRef, markdown, testWindow]);
 
   useEffect(() => {
     if (typeof document === "undefined") return;
+    const coarsePointer = isCoarsePointerDevice();
+    const clearSelectionCaptureTimeout = () => {
+      if (selectionCaptureTimeoutRef.current === null) return;
+      window.clearTimeout(selectionCaptureTimeoutRef.current);
+      selectionCaptureTimeoutRef.current = null;
+    };
+    const applySelectionChange = () => {
+      const captureStartedAt = selectionDebugEnabled ? performance.now() : 0;
+      const anchor = captureSelection();
+      if (anchor === undefined) return;
+      if (selectionDebugEnabled) {
+        recordCaptureSelection(performance.now() - captureStartedAt, Boolean(anchor));
+      }
+      if (!anchor) {
+        if (hasProcessedSelectionRef.current && lastProcessedSelectionRef.current === null) return;
+        lastProcessedSelectionRef.current = null;
+        hasProcessedSelectionRef.current = true;
+        onPendingAnchorChange(null);
+        setToolbarPosition(null);
+        return;
+      }
+      onPendingAnchorChange(anchor);
+    };
+    const scheduleSelectionCapture = (delay: number) => {
+      clearSelectionCaptureTimeout();
+      selectionCaptureTimeoutRef.current = window.setTimeout(() => {
+        selectionCaptureTimeoutRef.current = null;
+        applySelectionChange();
+      }, delay);
+    };
     const handleSelectionChange = () => {
       const selection = window.getSelection();
       const range = selection && selection.rangeCount > 0 ? selection.getRangeAt(0) : null;
@@ -443,20 +526,27 @@ export function DocumentAnnotationLayer({
         selection && !selection.isCollapsed && range && containerRef.current?.contains(range.commonAncestorContainer),
       );
       if (selectionDebugEnabled) recordSelectionChange(selectionIsActive);
-      const captureStartedAt = selectionDebugEnabled ? performance.now() : 0;
-      const anchor = captureSelection();
-      if (selectionDebugEnabled) {
-        recordCaptureSelection(performance.now() - captureStartedAt, Boolean(anchor));
-      }
-      if (!anchor) {
-        onPendingAnchorChange(null);
-        setToolbarPosition(null);
+      if (coarsePointer) {
+        scheduleSelectionCapture(COARSE_SELECTION_SETTLE_MS);
         return;
       }
-      onPendingAnchorChange(anchor);
+      applySelectionChange();
+    };
+    const handleGestureEnd = () => {
+      if (selectionCaptureTimeoutRef.current === null) return;
+      scheduleSelectionCapture(COARSE_GESTURE_END_CAPTURE_MS);
     };
     document.addEventListener("selectionchange", handleSelectionChange);
-    return () => document.removeEventListener("selectionchange", handleSelectionChange);
+    if (coarsePointer) {
+      document.addEventListener("pointerup", handleGestureEnd);
+      document.addEventListener("touchend", handleGestureEnd);
+    }
+    return () => {
+      clearSelectionCaptureTimeout();
+      document.removeEventListener("selectionchange", handleSelectionChange);
+      document.removeEventListener("pointerup", handleGestureEnd);
+      document.removeEventListener("touchend", handleGestureEnd);
+    };
   }, [captureSelection, containerRef, onPendingAnchorChange, selectionDebugEnabled]);
 
   useEffect(() => {
@@ -465,11 +555,11 @@ export function DocumentAnnotationLayer({
     if (lastCaptureSelectionRequestIdRef.current === captureSelectionRequestId) return;
     lastCaptureSelectionRequestIdRef.current = captureSelectionRequestId;
     const anchor = captureSelection();
-    if (anchor) {
-      onPendingAnchorChange(anchor);
-      onRequestComment(anchor);
-    }
-  }, [captureSelectionRequestId, captureSelection, onPendingAnchorChange, onRequestComment]);
+    const requestedAnchor = anchor === undefined ? pendingAnchor : anchor;
+    if (!requestedAnchor) return;
+    if (anchor !== undefined) onPendingAnchorChange(anchor);
+    onRequestComment(requestedAnchor);
+  }, [captureSelectionRequestId, captureSelection, onPendingAnchorChange, onRequestComment, pendingAnchor]);
 
   const handleAddComment = () => {
     if (pendingAnchor) onRequestComment(pendingAnchor);
diff --git a/ui/src/components/DocumentAnnotationPanel.tsx b/ui/src/components/DocumentAnnotationPanel.tsx
index e2c030ae691..c92684b2659 100644
--- a/ui/src/components/DocumentAnnotationPanel.tsx
+++ b/ui/src/components/DocumentAnnotationPanel.tsx
@@ -26,6 +26,7 @@ import { cn, relativeTime } from "@/lib/utils";
 import { documentAnnotationsApi, type DocumentAnnotationTarget } from "@/api/document-annotations";
 import { authApi } from "@/api/auth";
 import { queryKeys } from "@/lib/queryKeys";
+import { hasActiveNativeSelection, isCoarsePointerDevice } from "@/lib/document-annotation-selection";
 import { AgentIcon } from "./AgentIconPicker";
 import { deriveInitials } from "./Identity";
 import { MarkdownBody } from "./MarkdownBody";
@@ -71,6 +72,7 @@ export function DocumentAnnotationPanel(props: AnnotationPanelProps) {
         <SheetContent
           side="bottom"
           showCloseButton={false}
+          onOpenAutoFocus={(event) => event.preventDefault()}
           className="paperclip-doc-annotation-sheet z-(--z-60) flex max-h-(--sz-88vh) flex-col rounded-none border-t border-border bg-popover p-0 text-popover-foreground shadow-2xl"
         >
           <SheetTitle className="sr-only">
@@ -309,10 +311,10 @@ function AnnotationPanelBody(props: AnnotationPanelProps) {
   }, [props.open]);
 
   useEffect(() => {
-    if (props.pendingAnchor && props.open) {
-      composerRef.current?.focus();
-    }
-  }, [props.open, props.pendingAnchor]);
+    if (!props.pendingAnchor || !props.open || props.isMobile) return;
+    if (isCoarsePointerDevice() || hasActiveNativeSelection()) return;
+    composerRef.current?.focus();
+  }, [props.isMobile, props.open, props.pendingAnchor]);
 
   // Keep the comment list congruent with the document: when a thread becomes
   // focused — whether by clicking its highlight in the doc or by adding a new
diff --git a/ui/src/components/IssueDocumentAnnotations.test.tsx b/ui/src/components/IssueDocumentAnnotations.test.tsx
index 1af735cd53c..4998e87badb 100644
--- a/ui/src/components/IssueDocumentAnnotations.test.tsx
+++ b/ui/src/components/IssueDocumentAnnotations.test.tsx
@@ -1011,4 +1011,51 @@ describe("IssueDocumentAnnotations", () => {
       });
     }
   });
+
+  it("does not auto-focus the composer after a coarse-pointer selection request", async () => {
+    const originalMatchMedia = window.matchMedia;
+    Object.defineProperty(window, "matchMedia", {
+      configurable: true,
+      value: vi.fn().mockImplementation((query: string) => ({
+        matches: query === "(pointer: coarse)" || query === "(max-width: 767px)",
+        media: query,
+        onchange: null,
+        addEventListener: vi.fn(),
+        removeEventListener: vi.fn(),
+        addListener: vi.fn(),
+        removeListener: vi.fn(),
+        dispatchEvent: vi.fn(),
+      })),
+    });
+    const focusSpy = vi.spyOn(HTMLTextAreaElement.prototype, "focus").mockImplementation(() => {});
+    mockAnnotationsApi.list.mockResolvedValue([]);
+    const root = createRoot(container);
+    const queryClient = makeQueryClient();
+    const doc = makeDoc();
+
+    try {
+      await act(async () => {
+        root.render(
+          <QueryClientProvider client={queryClient}>
+            <Harness doc={doc} initialPanelOpen={false} />
+          </QueryClientProvider>,
+        );
+      });
+      await flush();
+      await flush();
+
+      const selectButton = container.querySelector<HTMLButtonElement>('[data-testid="mock-annotation-selection"]');
+      await act(async () => selectButton?.click());
+      await flush();
+
+      expect(container.querySelector('[data-testid="document-annotation-composer"]')).not.toBeNull();
+      expect(focusSpy).not.toHaveBeenCalled();
+    } finally {
+      focusSpy.mockRestore();
+      Object.defineProperty(window, "matchMedia", {
+        configurable: true,
+        value: originalMatchMedia,
+      });
+    }
+  });
 });
diff --git a/ui/src/lib/document-annotation-selection.ts b/ui/src/lib/document-annotation-selection.ts
index dfaf5c7906a..44349f469d9 100644
--- a/ui/src/lib/document-annotation-selection.ts
+++ b/ui/src/lib/document-annotation-selection.ts
@@ -19,6 +19,21 @@ export interface ContainerTextOffset {
   selectedText: string;
 }
 
+export function isCoarsePointerDevice(targetWindow: Window = window): boolean {
+  const navigatorWithLegacyTouchPoints = targetWindow.navigator as Navigator & {
+    msMaxTouchPoints?: number;
+  };
+  if ((navigatorWithLegacyTouchPoints.maxTouchPoints ?? 0) > 0) return true;
+  if ((navigatorWithLegacyTouchPoints.msMaxTouchPoints ?? 0) > 0) return true;
+  return typeof targetWindow.matchMedia === "function"
+    && targetWindow.matchMedia("(pointer: coarse)").matches;
+}
+
+export function hasActiveNativeSelection(targetWindow: Window = window): boolean {
+  const selection = targetWindow.getSelection();
+  return Boolean(selection && selection.rangeCount > 0 && !selection.isCollapsed);
+}
+
 export function getContainerTextOffset(
   container: HTMLElement,
   range: Range,