make clicking on comments open the comments sidebar and more (#6174)

make clicking on comments open the comments sidebar and add a button to
create comments into the empty state of the comments sidebar
<img width="2056" height="1081" alt="Screenshot 2026-04-23 at 12 39
50 PM"
src="https://github.com/user-attachments/assets/6f15484d-d04f-4900-92c6-b2cc397d6d08"
/>

<img width="627" height="396" alt="Screenshot 2026-04-23 at 12 40 06 PM"
src="https://github.com/user-attachments/assets/509e5526-0082-4fc6-a98f-829bb4c1baf2"
/>

frontend/src/core/components/viewer/AnnotationSelectionMenu.tsx

@@ -1,6 +1,6 @@
 import { Group } from "@mantine/core";
 import { createPortal } from "react-dom";
-import { useEffect, useState, useRef, useCallback } from "react";
+import { useEffect, useState, useRef, useCallback, useMemo } from "react";
 import { useAnnotation } from "@embedpdf/plugin-annotation/react";
 import type { TrackedAnnotation } from "@embedpdf/plugin-annotation";
 import {
@@ -47,7 +47,7 @@ function AnnotationSelectionMenuInner({
 }: AnnotationSelectionMenuProps & { documentId: string }) {
   const annotation = context?.annotation;
   const pageIndex = context?.pageIndex;
-  const { provides } = useAnnotation(documentId);
+  const { state, provides } = useAnnotation(documentId);
   const { scrollActions, requestCommentFocus } = useViewer();
   const wrapperRef = useRef<HTMLDivElement>(null);
   const [menuPosition, setMenuPosition] = useState<{
@@ -65,17 +65,52 @@ function AnnotationSelectionMenuInner({
     wrapperRef,
   });
 
+  // Read isInSidebar from live EmbedPDF state rather than annotation.object, which can be
+  // stale after updateAnnotation() is called while the annotation is selected.
+  // Also checks non-empty contents: customData.isComment is not persisted to PDF, but
+  // contents is a standard PDF field and survives save/reload.
+  const isInSidebar = useMemo(() => {
+    const annId = (annotation?.object as AnnotationObject | undefined)?.id;
+    if (!annId) return false;
+    for (const tracked of Object.values(state.byUid)) {
+      const obj = tracked.object;
+      if (obj.id !== annId) continue;
+      const { type } = obj;
+      // TEXT and CARET are standalone comment annotations — they use CommentButton,
+      // not AttachCommentButton, so isInSidebar is irrelevant for them.
+      if (
+        type === PdfAnnotationSubtype.TEXT ||
+        type === PdfAnnotationSubtype.CARET
+      )
+        return false;
+      // customData is a runtime field EmbedPDF adds but doesn't declare in its TS types
+      const customData = (
+        obj as unknown as { customData?: Record<string, unknown> }
+      ).customData;
+      const isExplicit = customData?.isComment === true;
+      // customData (incl. toolId/isComment) is not persisted to PDF; contents is.
+      // Any non-TEXT/FreeText/CARET annotation with non-empty contents has a comment.
+      const hasContents =
+        type !== PdfAnnotationSubtype.FREETEXT &&
+        !obj.inReplyToId &&
+        (obj.contents ?? "").trim().length > 0;
+      return isExplicit || hasContents;
+    }
+    return false;
+  }, [state, annotation?.object]);
+
   // Auto-open the comments sidebar when a comment annotation is selected
   useEffect(() => {
     const annObj = annotation?.object as AnnotationObject | undefined;
     const annId = annObj?.id;
     if (!selected || !annId || pageIndex === undefined) return;
-    const toolId = annObj?.customData?.toolId;
     const annType = annObj?.type;
+    // TEXT (type 1) = textComment; CARET (type 14) = insertText/replaceText.
+    // These are always comment annotations regardless of toolId (lost after reload).
     const isComment =
-      (annType === PdfAnnotationSubtype.TEXT && toolId === "textComment") ||
+      annType === PdfAnnotationSubtype.TEXT ||
-      (annType === PdfAnnotationSubtype.CARET &&
+      annType === PdfAnnotationSubtype.CARET ||
-        (toolId === "insertText" || toolId === "replaceText"));
+      isInSidebar;
     if (!isComment) return;
     requestCommentFocus(
       documentId,
@@ -83,7 +118,7 @@ function AnnotationSelectionMenuInner({
       annId,
       (annObj?.contents ?? "").trim().length > 0,
     );
-  }, [selected, annotation?.object]);
+  }, [selected, annotation?.object, isInSidebar]);
 
   // Click outside to deselect
   useEffect(() => {
@@ -170,6 +205,7 @@ function AnnotationSelectionMenuInner({
       <Group gap="sm" wrap="nowrap" justify="center">
         <AnnotationTypeButtons
           {...handlers}
+          isInSidebar={isInSidebar}
           annotation={annotation}
           documentId={documentId}
           pageIndex={pageIndex}

frontend/src/core/components/viewer/AnnotationTypeButtons.tsx

@@ -58,9 +58,13 @@ export function AnnotationTypeButtons(props: AnnotationTypeButtonsProps) {
     onCommentColorChange,
   } = props;
 
-  const attachCommentButton = (
+  // When a comment is attached, show the same chat-bubble "View comment" button used by
+  // standalone comment annotations. When no comment, show the "Add comment" attach button.
+  const attachCommentButton = isInSidebar ? (
+    <CommentButton hasContent={hasCommentContent} onClick={onViewComment} />
+  ) : (
     <AttachCommentButton
-      isInSidebar={isInSidebar}
+      isInSidebar={false}
       onView={onViewComment}
       onAdd={onAddToSidebar}
     />
@@ -221,10 +225,6 @@ export function AnnotationTypeButtons(props: AnnotationTypeButtonsProps) {
       return (
         <>
           {attachCommentButton}
-          <CommentButton
-            hasContent={hasCommentContent}
-            onClick={onViewComment}
-          />
           <LinkButton
             firstLinkTarget={firstLinkTarget}
             onGoToLink={onGoToLink}

frontend/src/core/components/viewer/CommentsSidebar.tsx

@@ -22,13 +22,37 @@ import EditIcon from "@mui/icons-material/Edit";
 import VisibilityIcon from "@mui/icons-material/Visibility";
 import { useAnnotation } from "@embedpdf/plugin-annotation/react";
 import { getSidebarAnnotationsWithRepliesGroupedByPage } from "@embedpdf/plugin-annotation";
-import { PdfAnnotationSubtype, PdfAnnotationReplyType } from "@embedpdf/models";
+import {
+  PdfAnnotationSubtype,
+  PdfAnnotationReplyType,
+  type PdfAnnotationObject,
+  type PdfTextAnnoObject,
+} from "@embedpdf/models";
 import { useCommentAuthor } from "@app/contexts/CommentAuthorContext";
 import { useViewer } from "@app/contexts/ViewerContext";
+import { useToolWorkflow } from "@app/contexts/ToolWorkflowContext";
+import { useAnnotation as useAnnotationContext } from "@app/contexts/AnnotationContext";
 import LocalIcon from "@app/components/shared/LocalIcon";
 
 const SIDEBAR_WIDTH = "18rem";
 
+/** PDF subtypes that are inherently standalone comment annotations (not linked to other annotations). */
+const STANDALONE_COMMENT_SUBTYPES = new Set([
+  PdfAnnotationSubtype.TEXT,
+  PdfAnnotationSubtype.FREETEXT,
+  PdfAnnotationSubtype.CARET,
+]);
+
+function isStandaloneCommentType(type: number | undefined): boolean {
+  return (
+    type !== undefined &&
+    STANDALONE_COMMENT_SUBTYPES.has(type as PdfAnnotationSubtype)
+  );
+}
+
+const ANNOTATE_PANEL_ID = "annotate" as const;
+const TEXT_COMMENT_TOOL_ID = "textComment" as const;
+
 /** Format annotation date for display (e.g. "Mar 11, 6:05 PM"). */
 function formatCommentDate(obj: any): string {
   const raw =
@@ -143,8 +167,20 @@ function isCommentAnnotation(ann: any): boolean {
     return true;
   // Any annotation explicitly added to comments via the "Add comment" button
   if (ann?.customData?.isComment === true) return true;
-  // CARET (type 14) = insertText/replaceText; TEXT (type 1) = textComment
+  const type = ann?.type;
-  if (!toolId && (ann?.type === 14 || ann?.type === 1)) return true;
+  // Standalone comment types (TEXT, FREETEXT, CARET) without a toolId are always comments
+  if (!toolId && isStandaloneCommentType(type)) return true;
+  // Non-standalone annotations with non-empty contents: customData (including isComment and
+  // toolId) is NOT persisted to PDF, but `contents` is a standard PDF field and survives
+  // save/reload. Exclude standalone comment types (TEXT, FREETEXT, CARET) which use
+  // `contents` for their own annotation text. Exclude replies.
+  if (
+    type !== undefined &&
+    !isStandaloneCommentType(type) &&
+    !ann?.inReplyToId &&
+    (ann?.contents ?? "").trim().length > 0
+  )
+    return true;
   return false;
 }
 
@@ -213,6 +249,8 @@ export function CommentsSidebar({
   } = useViewer() ?? {};
   const scrollViewportRef = useRef<HTMLDivElement | null>(null);
   const { state, provides } = useAnnotation(documentId);
+  const { handleToolSelectForced } = useToolWorkflow();
+  const { activateAnnotationToolRef } = useAnnotationContext();
   const [draftContents, setDraftContents] = useState<Record<string, string>>(
     {},
   );
@@ -324,8 +362,8 @@ export function CommentsSidebar({
       const all = getSidebarAnnotationsWithRepliesGroupedByPage(state) ?? {};
       const filtered: typeof all = {};
       for (const [page, entries] of Object.entries(all)) {
-        const commentEntries = (entries as typeof entries).filter((e) =>
+        const commentEntries = entries.filter((e) =>
-          isCommentAnnotation((e as any).annotation?.object),
+          isCommentAnnotation(e.annotation.object),
         );
         if (commentEntries.length > 0) {
           filtered[Number(page)] = commentEntries;
@@ -341,12 +379,11 @@ export function CommentsSidebar({
   // state is AnnotationDocumentState — selectedUids are keys in byUid, and may equal id.
   const selectedAnnotationIds = useMemo(() => {
     const selectedUids: string[] = state?.selectedUids ?? [];
-    const byUid: Record<string, any> = (state as any)?.byUid ?? {};
     const ids = new Set<string>();
     for (const uid of selectedUids) {
       // uid itself may be the annotation id
       ids.add(uid);
-      const annId = byUid[uid]?.object?.id;
+      const annId = state.byUid[uid]?.object.id;
       if (annId) ids.add(annId);
     }
     return ids;
@@ -383,12 +420,12 @@ export function CommentsSidebar({
   } | null>(null);
 
   const isLinkedAnnotation = (ann: any) => {
-    const toolId = ann?.customData?.toolId ?? ann?.customData?.annotationToolId;
+    const type = ann?.type;
+    if (isStandaloneCommentType(type)) return false;
+    if (ann?.inReplyToId) return false;
     return (
-      ann?.customData?.isComment === true &&
+      ann?.customData?.isComment === true ||
-      toolId !== "textComment" &&
+      (type !== undefined && (ann?.contents ?? "").trim().length > 0)
-      toolId !== "insertText" &&
-      toolId !== "replaceText"
     );
   };
 
@@ -408,7 +445,13 @@ export function CommentsSidebar({
     const { pageIndex, id, ann } = deleteModal;
     const existing = (ann?.customData ?? {}) as Record<string, unknown>;
     const { isComment: _removed, ...rest } = existing;
-    provides.updateAnnotation(pageIndex, id, { customData: rest } as any);
+    // Also clear contents: the contents field is the persisted signal for
+    // post-reload linked annotations, so clearing it removes the annotation
+    // from the sidebar (contents is not visually rendered on ink/shape/markup types).
+    provides.updateAnnotation(pageIndex, id, {
+      customData: rest,
+      contents: "",
+    } as unknown as Partial<PdfAnnotationObject>);
     setDeleteModal(null);
   }, [deleteModal, provides]);
 
@@ -443,7 +486,7 @@ export function CommentsSidebar({
         origin: { x: 0, y: 0 },
         size: { width: 1, height: 1 },
       };
-      provides.createAnnotation(pageIndex, {
+      const reply: PdfTextAnnoObject = {
         type: PdfAnnotationSubtype.TEXT,
         id: `reply-${Date.now()}-${Math.random().toString(36).slice(2, 9)}`,
         pageIndex,
@@ -452,7 +495,8 @@ export function CommentsSidebar({
         inReplyToId: parentId,
         replyType: PdfAnnotationReplyType.Reply,
         author: displayName,
-      } as any);
+      };
+      provides.createAnnotation(pageIndex, reply);
       setReplyDrafts((prev) => ({ ...prev, [key]: "" }));
     },
     [provides, replyDrafts, displayName],
@@ -476,6 +520,13 @@ export function CommentsSidebar({
     [provides, displayName],
   );
 
+  const handleAddComment = useCallback(() => {
+    handleToolSelectForced(ANNOTATE_PANEL_ID);
+    requestAnimationFrame(() => {
+      activateAnnotationToolRef.current?.(TEXT_COMMENT_TOOL_ID);
+    });
+  }, [handleToolSelectForced, activateAnnotationToolRef]);
+
   if (!visible) return null;
 
   return (
@@ -510,19 +561,49 @@ export function CommentsSidebar({
           height="1.25rem"
           style={{ color: "var(--mantine-color-dimmed)", flexShrink: 0 }}
         />
-        <Text fw={600} size="sm" tt="uppercase" lts={0.5}>
+        <Text fw={600} size="sm" tt="uppercase" lts={0.5} style={{ flex: 1 }}>
           {t("viewer.comments.title", "Comments")}
         </Text>
+        {totalCount > 0 && (
+          <Tooltip label={t("viewer.comments.addComment", "Add comment")}>
+            <ActionIcon
+              variant="subtle"
+              size="sm"
+              color="gray"
+              onClick={handleAddComment}
+            >
+              <LocalIcon icon="add" width="1.25rem" height="1.25rem" />
+            </ActionIcon>
+          </Tooltip>
+        )}
       </div>
       <ScrollArea style={{ flex: 1 }}>
         <Stack p="sm" gap="md">
           {totalCount === 0 ? (
-            <Text size="sm" c="dimmed">
+            <Stack align="center" gap="sm" py="lg">
+              <LocalIcon
+                icon="comment"
+                width="2rem"
+                height="2rem"
+                style={{ color: "var(--mantine-color-dimmed)" }}
+              />
+              <Text size="sm" c="dimmed" ta="center">
                 {t(
                   "viewer.comments.hint",
                   "Place comments with the Comment, Insert Text, or Replace Text tools. They will appear here by page.",
                 )}
               </Text>
+              <Button
+                variant="light"
+                size="xs"
+                onClick={handleAddComment}
+                leftSection={
+                  <LocalIcon icon="add" width="1rem" height="1rem" />
+                }
+              >
+                {t("viewer.comments.addComment", "Add comment")}
+              </Button>
+            </Stack>
           ) : (
             pageNumbers.map((pageIndex) => {
               const entries = byPage[pageIndex] ?? [];

frontend/src/core/components/viewer/useAnnotationMenuHandlers.ts

@@ -27,6 +27,32 @@ export type AnnotationType =
   | "stamp"
   | "unknown";
 
+const TEXT_MARKUP_SUBTYPES = [
+  PdfAnnotationSubtype.HIGHLIGHT,
+  PdfAnnotationSubtype.UNDERLINE,
+  PdfAnnotationSubtype.SQUIGGLY,
+  PdfAnnotationSubtype.STRIKEOUT,
+];
+
+const SHAPE_SUBTYPES = [
+  PdfAnnotationSubtype.SQUARE,
+  PdfAnnotationSubtype.CIRCLE,
+  PdfAnnotationSubtype.POLYGON,
+];
+
+const LINE_SUBTYPES = [
+  PdfAnnotationSubtype.LINE,
+  PdfAnnotationSubtype.POLYLINE,
+];
+
+const STROKE_COLOR_SUBTYPES = [
+  PdfAnnotationSubtype.LINE,
+  PdfAnnotationSubtype.SQUARE,
+  PdfAnnotationSubtype.CIRCLE,
+  PdfAnnotationSubtype.POLYGON,
+  PdfAnnotationSubtype.POLYLINE,
+];
+
 export type FirstLinkTarget =
   | { type: "uri"; uri: string }
   | { type: "goto"; pageIndex: number };
@@ -134,17 +160,36 @@ export function useAnnotationMenuHandlers({
     const toolId = (annotation?.object as AnnotationObject | undefined)
       ?.customData?.toolId;
 
-    if (type !== undefined && [9, 10, 11, 12].includes(type))
+    if (
+      type !== undefined &&
+      TEXT_MARKUP_SUBTYPES.includes(type as PdfAnnotationSubtype)
+    )
       return "textMarkup";
-    if (type === 15)
+    if (type === PdfAnnotationSubtype.INK)
       return toolId === "inkHighlighter" ? "inkHighlighter" : "ink";
-    if (type === 1 && toolId === "textComment") return "comment";
+    // TEXT and CARET fall back to type alone after save/reload (customData.toolId is absent).
-    if (type === 14 && (toolId === "insertText" || toolId === "replaceText"))
+    if (
+      type === PdfAnnotationSubtype.TEXT &&
+      (!toolId || toolId === "textComment")
+    )
       return "comment";
-    if (type === 3) return "note";
+    if (
-    if (type !== undefined && [5, 6, 7].includes(type)) return "shape";
+      type === PdfAnnotationSubtype.CARET &&
-    if (type !== undefined && [4, 8].includes(type)) return "line";
+      (!toolId || toolId === "insertText" || toolId === "replaceText")
-    if (type === 13) return "stamp";
+    )
+      return "comment";
+    if (type === PdfAnnotationSubtype.FREETEXT) return "note";
+    if (
+      type !== undefined &&
+      SHAPE_SUBTYPES.includes(type as PdfAnnotationSubtype)
+    )
+      return "shape";
+    if (
+      type !== undefined &&
+      LINE_SUBTYPES.includes(type as PdfAnnotationSubtype)
+    )
+      return "line";
+    if (type === PdfAnnotationSubtype.STAMP) return "stamp";
     return "unknown";
   }, [annotation]);
 
@@ -174,8 +219,12 @@ export function useAnnotationMenuHandlers({
   const currentColor = (() => {
     if (!obj) return "#000000";
     const type = obj.type;
-    if (type === 3) return obj.textColor || obj.color || "#000000";
+    if (type === PdfAnnotationSubtype.FREETEXT)
-    if (type !== undefined && [4, 5, 6, 7, 8].includes(type))
+      return obj.textColor || obj.color || "#000000";
+    if (
+      type !== undefined &&
+      STROKE_COLOR_SUBTYPES.includes(type as PdfAnnotationSubtype)
+    )
       return obj.strokeColor || obj.color || "#000000";
     return obj.color || obj.strokeColor || "#000000";
   })();
@@ -247,17 +296,23 @@ export function useAnnotationMenuHandlers({
         patch.contents = obj?.contents ?? "";
       } else {
         patch.color = color;
-        if (type !== undefined && [9, 10, 11, 12].includes(type)) {
+        if (
+          type !== undefined &&
+          TEXT_MARKUP_SUBTYPES.includes(type as PdfAnnotationSubtype)
+        ) {
           patch.strokeColor = color;
           patch.fillColor = color;
           patch.opacity = obj?.opacity ?? 1;
         }
-        if (type !== undefined && [4, 8].includes(type)) {
+        if (
+          type !== undefined &&
+          LINE_SUBTYPES.includes(type as PdfAnnotationSubtype)
+        ) {
           patch.strokeColor = color;
           patch.strokeWidth = obj?.strokeWidth ?? obj?.lineWidth ?? 2;
           patch.lineWidth = obj?.lineWidth ?? obj?.strokeWidth ?? 2;
         }
-        if (type === 15) {
+        if (type === PdfAnnotationSubtype.INK) {
           patch.strokeColor = color;
           patch.strokeWidth = obj?.strokeWidth ?? obj?.thickness ?? 2;
           patch.opacity = obj?.opacity ?? 1;

frontend/src/core/contexts/AnnotationContext.tsx

@@ -1,8 +1,15 @@
 import React, { createContext, useContext, ReactNode, useRef } from "react";
-import type { AnnotationAPI } from "@app/components/viewer/viewerTypes";
+import type {
+  AnnotationAPI,
+  AnnotationToolId,
+} from "@app/components/viewer/viewerTypes";
 
 interface AnnotationContextValue {
   annotationApiRef: React.RefObject<AnnotationAPI | null>;
+  /** Ref to the panel-level activateAnnotationTool function — updates React state so buttons highlight correctly. Populated by Annotate.tsx. */
+  activateAnnotationToolRef: React.RefObject<
+    ((toolId: AnnotationToolId) => void) | null
+  >;
 }
 
 const AnnotationContext = createContext<AnnotationContextValue | undefined>(
@@ -13,9 +20,13 @@ export const AnnotationProvider: React.FC<{ children: ReactNode }> = ({
   children,
 }) => {
   const annotationApiRef = useRef<AnnotationAPI>(null);
+  const activateAnnotationToolRef = useRef<
+    ((toolId: AnnotationToolId) => void) | null
+  >(null);
 
   const value: AnnotationContextValue = {
     annotationApiRef,
+    activateAnnotationToolRef,
   };
 
   return (

frontend/src/core/tools/Annotate.tsx

@@ -6,6 +6,7 @@ import { useNavigation } from "@app/contexts/NavigationContext";
 import { useFileSelection } from "@app/contexts/FileContext";
 import { BaseToolProps } from "@app/types/tool";
 import { useSignature } from "@app/contexts/SignatureContext";
+import { useAnnotation as useAnnotationContext } from "@app/contexts/AnnotationContext";
 import { ViewerContext, useViewer } from "@app/contexts/ViewerContext";
 import type {
   AnnotationToolId,
@@ -85,6 +86,7 @@ const Annotate = (_props: BaseToolProps) => {
     placementPreviewSize,
     setPlacementPreviewSize,
   } = useSignature();
+  const { activateAnnotationToolRef } = useAnnotationContext();
   const viewerContext = useContext(ViewerContext);
   const viewerContextRef = useRef(viewerContext);
   useEffect(() => {
@@ -375,6 +377,9 @@ const Annotate = (_props: BaseToolProps) => {
     }, 300);
   };
 
+  // Keep ref in sync so external callers (e.g. CommentsSidebar) get the latest closure
+  activateAnnotationToolRef.current = activateAnnotationTool;
+
   useEffect(() => {
     // push style updates to EmbedPDF when sliders/colors change
     if (activeTool === "stamp") {