feat(diff): unified comment UI with gutter plus and content-drag selection

The diff comment editor is restyled as the shared comment pill (context
line inside the box, auto-growing textarea, round attach button;
Cmd/Ctrl+Enter attaches, Enter breaks the line) and the saved-comment
card matches the composer preview entries. Pierre's gutter utility is
enabled: hovering a line shows a small primary-colored plus that opens
a comment for the line, dragging from it selects a range, and it rides
the bottom of an active selection. Clicking a diff line toggles a
single-line comment, and dragging over content maps to the same line
selection the number column produces — the native text selection is
suppressed once a drag crosses a line boundary — opening the editor for
the range on release. Placeholders and meta lines are dimmed relative
to typed text.

packages/ui/src/components/chat/message/TextSelectionMenu.tsx

@@ -616,7 +616,7 @@ export const TextSelectionMenu: React.FC<TextSelectionMenuProps> = ({ containerR
         }}
         placeholder={t('chat.textSelection.comment.placeholder')}
         className={cn(
-          'flex-1 resize-none bg-transparent text-sm leading-5 text-[var(--surface-foreground)] outline-none placeholder:text-[var(--surface-mutedForeground)]',
+          'flex-1 resize-none bg-transparent text-sm leading-5 text-[var(--surface-foreground)] outline-none placeholder:text-[var(--surface-mutedForeground)] placeholder:opacity-60',
           // The width cap sizes the floating desktop pill; on mobile the pill
           // spans the bottom bar and the cap would strand slack space to the
           // right of the attach button.

packages/ui/src/components/comments/InlineCommentCard.tsx

@@ -1,17 +1,9 @@
 import React, { useState } from 'react';
 import type { InlineCommentDraft } from '@/stores/useInlineCommentDraftStore';
-import { useOptionalThemeSystem } from '@/contexts/useThemeSystem';
-import {
-  DropdownMenu,
-  DropdownMenuContent,
-  DropdownMenuItem,
-  DropdownMenuTrigger,
-} from '@/components/ui/dropdown-menu';
-import { ContextMenu, ContextMenuContent, ContextMenuItem, ContextMenuTrigger } from '@/components/ui/context-menu';
 import { Button } from '@/components/ui/button';
 import { cn } from '@/lib/utils';
 import { Collapsible, CollapsibleContent, CollapsibleTrigger } from '@/components/ui/collapsible';
-import { Icon } from "@/components/icon/Icon";
+import { Icon } from '@/components/icon/Icon';
 import { useI18n } from '@/lib/i18n';
 
 interface InlineCommentCardProps {
@@ -22,6 +14,14 @@ interface InlineCommentCardProps {
   maxWidth?: number;
 }
 
+const HEADER_ACTION_CLASS = 'inline-flex h-5 w-5 shrink-0 items-center justify-center rounded-full text-[var(--surface-mutedForeground)] hover:bg-[var(--interactive-hover)] hover:text-[var(--surface-foreground)]';
+
+/**
+ * A saved inline comment shown under its lines in the diff/editor. Styled to
+ * match the composer's context preview entries: a muted header band naming
+ * the file and range with direct edit/remove actions, and the comment text
+ * below.
+ */
 export function InlineCommentCard({
   draft,
   onEdit,
@@ -30,115 +30,90 @@ export function InlineCommentCard({
   maxWidth,
 }: InlineCommentCardProps) {
   const { t } = useI18n();
-  const themeContext = useOptionalThemeSystem();
-  const currentTheme = themeContext?.currentTheme;
   const [isOpen, setIsOpen] = useState(false);
-  const [isContextMenuOpen, setIsContextMenuOpen] = useState(false);
+  const draftText = draft.text;
-  const draftText = typeof draft.text === 'string' ? draft.text : '';
 
   // Check if content is long enough to warrant collapsing (rough estimate)
-  // In a real app we might measure line height, but length check is a good proxy for now
   const isLongContent = draftText.length > 150 || draftText.split('\n').length > 3;
 
   return (
-    <ContextMenu open={isContextMenuOpen} onOpenChange={setIsContextMenuOpen}>
+    <div
-      <ContextMenuTrigger
+      className={cn(
-        render={
+        'w-full max-w-[min(100%,calc(var(--oc-context-panel-width,100vw)-var(--oc-editor-gutter-width,0px)))] overflow-hidden rounded-xl border border-[var(--interactive-border)] bg-[var(--surface-elevated)] shadow-none',
-          <div
+        className
-            className={cn(
+      )}
-              "rounded-lg border shadow-none w-full max-w-[min(100%,calc(var(--oc-context-panel-width,100vw)-var(--oc-editor-gutter-width,0px)))] overflow-hidden transition-all duration-200",
+      style={{
-              className
+        maxWidth: maxWidth ? `${Math.max(200, Math.floor(maxWidth))}px` : undefined,
-            )}
+      }}
-            style={{
+      data-comment-card="true"
-              backgroundColor: currentTheme?.colors?.surface?.elevated,
+    >
-              borderColor: currentTheme?.colors?.interactive?.border,
+      <div
-              maxWidth: maxWidth ? `${Math.max(200, Math.floor(maxWidth))}px` : undefined,
+        className="flex items-center gap-1.5 px-3 py-1.5"
-            }}
+        style={{ backgroundColor: 'color-mix(in srgb, var(--surface-mutedForeground) 8%, transparent)' }}
-            data-comment-card="true"
-            onContextMenu={(event) => {
-              event.preventDefault();
-              setIsContextMenuOpen(true);
-            }}
-          />
-        }
       >
-      <div className="flex items-start justify-between gap-2 p-3">
+        <span className="min-w-0 max-w-[200px] truncate text-xs font-medium text-[var(--surface-foreground)]" title={draft.fileLabel}>
-        <div className="flex-1 min-w-0">
+          {draft.fileLabel}
-          <div className="flex items-center gap-2 text-xs font-medium text-muted-foreground mb-1.5">
+        </span>
-            <span className="truncate max-w-[200px]" title={draft.fileLabel}>
+        <span className="text-xs text-[var(--surface-mutedForeground)]">•</span>
-              {draft.fileLabel}
+        <span className="min-w-0 flex-1 truncate text-xs text-[var(--surface-mutedForeground)]">
-            </span>
+          {t('inlineComment.range.lines', { start: draft.startLine, end: draft.endLine })}
-            <span>•</span>
+          {draft.side ? ` (${draft.side})` : ''}
-            <span>{t('inlineComment.range.lines', { start: draft.startLine, end: draft.endLine })}</span>
+        </span>
-            {draft.side && <span>({draft.side})</span>}
+        <button
+          type="button"
+          className={HEADER_ACTION_CLASS}
+          style={{ minHeight: 0, minWidth: 0 }}
+          onClick={onEdit}
+          aria-label={t('inlineComment.actions.editComment')}
+          title={t('inlineComment.actions.editComment')}
+        >
+          <Icon name="pencil" className="h-3 w-3" />
+        </button>
+        <button
+          type="button"
+          className={HEADER_ACTION_CLASS}
+          style={{ minHeight: 0, minWidth: 0 }}
+          onClick={onDelete}
+          aria-label={t('inlineComment.actions.deleteComment')}
+          title={t('inlineComment.actions.deleteComment')}
+        >
+          <Icon name="close" className="h-3 w-3" />
+        </button>
+      </div>
+
+      <div className="px-3 py-2">
+        <Collapsible open={isOpen || !isLongContent} onOpenChange={setIsOpen}>
+          <div className={cn('whitespace-pre-wrap break-words text-sm leading-relaxed text-[var(--surface-foreground)]', !isOpen && isLongContent && 'line-clamp-3')}>
+            {draftText}
           </div>
 
-          <Collapsible open={isOpen || !isLongContent} onOpenChange={setIsOpen}>
+          {isLongContent && (
-            <div className={cn("text-sm whitespace-pre-wrap break-words leading-relaxed", !isOpen && isLongContent && "line-clamp-3")}>
+            <CollapsibleTrigger asChild>
-              {draftText}
+              <Button
-            </div>
+                variant="ghost"
+                size="sm"
+                className="mt-1 h-6 w-full justify-start px-0 text-xs text-muted-foreground hover:text-foreground"
+              >
+                {isOpen ? (
+                  <>
+                    <Icon name="arrow-up-s" className="mr-1 size-3" />
+                    {t('inlineComment.actions.showLess')}
+                  </>
+                ) : (
+                  <>
+                    <Icon name="arrow-down-s" className="mr-1 size-3" />
+                    {t('inlineComment.actions.showMore')}
+                  </>
+                )}
+              </Button>
+            </CollapsibleTrigger>
+          )}
 
-            {isLongContent && (
+          <CollapsibleContent>
-              <CollapsibleTrigger asChild>
+            {/* Used for animation purposes if we want to animate height */}
-                <Button 
+          </CollapsibleContent>
-                  variant="ghost" 
+        </Collapsible>
-                  size="sm" 
-                  className="h-6 px-0 mt-1 text-xs text-muted-foreground hover:text-foreground w-full justify-start"
-                >
-                  {isOpen ? (
-                    <>
-                      <Icon name="arrow-up-s" className="size-3 mr-1" />
-                      {t('inlineComment.actions.showLess')}
-                    </>
-                  ) : (
-                    <>
-                      <Icon name="arrow-down-s" className="size-3 mr-1" />
-                      {t('inlineComment.actions.showMore')}
-                    </>
-                  )}
-                </Button>
-              </CollapsibleTrigger>
-            )}
-            
-            <CollapsibleContent>
-              {/* Used for animation purposes if we want to animate height */}
-            </CollapsibleContent>
-          </Collapsible>
-        </div>
-
-        <DropdownMenu>
-          <DropdownMenuTrigger asChild>
-            <Button
-              variant="ghost"
-              size="icon"
-              className="h-6 w-6 -mr-1 text-muted-foreground hover:text-foreground"
-            >
-              <Icon name="more" className="size-4" />
-            </Button>
-          </DropdownMenuTrigger>
-          <DropdownMenuContent align="end">
-            <DropdownMenuItem onClick={onEdit}>
-              <Icon name="edit" className="size-4 mr-2" />
-              {t('inlineComment.actions.editComment')}
-            </DropdownMenuItem>
-            <DropdownMenuItem onClick={onDelete} className="text-destructive">
-              <Icon name="delete-bin" className="size-4 mr-2" />
-              {t('inlineComment.actions.deleteComment')}
-            </DropdownMenuItem>
-          </DropdownMenuContent>
-        </DropdownMenu>
       </div>
-      </ContextMenuTrigger>
+    </div>
-      <ContextMenuContent>
-        <ContextMenuItem onClick={onEdit}>
-          <Icon name="edit" className="size-4 mr-2" />
-          {t('inlineComment.actions.editComment')}
-        </ContextMenuItem>
-        <ContextMenuItem onClick={onDelete} className="text-destructive focus:text-destructive">
-          <Icon name="delete-bin" className="size-4 mr-2" />
-          {t('inlineComment.actions.deleteComment')}
-        </ContextMenuItem>
-      </ContextMenuContent>
-    </ContextMenu>
   );
 }

packages/ui/src/components/comments/InlineCommentInput.tsx

@@ -1,8 +1,6 @@
 import React, { useRef, useEffect } from 'react';
-import { useOptionalThemeSystem } from '@/contexts/useThemeSystem';
-import { Button } from '@/components/ui/button';
-import { Textarea } from '@/components/ui/textarea';
 import { cn } from '@/lib/utils';
+import { Icon } from '@/components/icon/Icon';
 import { useDeviceInfo } from '@/lib/device';
 import { useI18n } from '@/lib/i18n';
 
@@ -18,6 +16,12 @@ export interface InlineCommentInputProps {
   maxWidth?: number;
 }
 
+/**
+ * The comment editor shown under selected diff/editor lines. Styled as the
+ * same pill used by chat quote comments and browser annotations: a rounded
+ * auto-growing textarea with a round attach button, and a muted context line
+ * above naming the file and range.
+ */
 export function InlineCommentInput({
   initialText = '',
   onTextChange,
@@ -30,15 +34,22 @@ export function InlineCommentInput({
   maxWidth,
 }: InlineCommentInputProps) {
   const { t } = useI18n();
-  const themeContext = useOptionalThemeSystem();
-  const currentTheme = themeContext?.currentTheme;
   const { isMobile } = useDeviceInfo();
   const [text, setText] = React.useState(initialText);
   const textareaRef = useRef<HTMLTextAreaElement>(null);
+  void isEditing;
 
   const handleTextChange = (value: string) => {
     setText(value);
     onTextChange?.(value);
+    resizeTextarea();
+  };
+
+  const resizeTextarea = () => {
+    const element = textareaRef.current;
+    if (!element) return;
+    element.style.height = 'auto';
+    element.style.height = `${Math.min(element.scrollHeight, 120)}px`;
   };
 
   // Stable range snapshot to prevent race with selection clearing
@@ -62,8 +73,9 @@ export function InlineCommentInput({
   useEffect(() => {
     const textarea = textareaRef.current;
     if (!textarea) return;
+    resizeTextarea();
 
-    const scrollContainer = textarea.closest('.overlay-scrollbar-container') as HTMLElement | null;
+    const scrollContainer = textarea.closest<HTMLElement>('.overlay-scrollbar-container');
     const prevScrollTop = scrollContainer?.scrollTop ?? window.scrollY;
     const prevScrollLeft = scrollContainer?.scrollLeft ?? window.scrollX;
 
@@ -100,12 +112,18 @@ export function InlineCommentInput({
     });
   }, [isMobile]);
 
+  const save = () => {
+    if (text.trim()) {
+      onSave(text, normalizeRange(stableRangeRef.current));
+    }
+  };
+
   const handleKeyDown = (e: React.KeyboardEvent) => {
+    // As the placeholder promises: Cmd/Ctrl+Enter attaches, plain Enter
+    // breaks the line, Escape cancels.
     if ((e.metaKey || e.ctrlKey) && e.key === 'Enter') {
       e.preventDefault();
-      if (text.trim()) {
+      save();
-        onSave(text, normalizeRange(stableRangeRef.current));
-      }
     } else if (e.key === 'Escape') {
       e.preventDefault();
       onCancel();
@@ -115,75 +133,61 @@ export function InlineCommentInput({
   const handleSaveClick = (e: React.MouseEvent | React.TouchEvent | React.PointerEvent) => {
     // Stop propagation to prevent parent selection clearing before save
     e.stopPropagation();
-    if (text.trim()) {
+    save();
-      onSave(text, normalizeRange(stableRangeRef.current));
-    }
   };
 
   return (
     <div
       className={cn(
-        "rounded-lg border shadow-none w-full max-w-[min(100%,calc(var(--oc-context-panel-width,100vw)-var(--oc-editor-gutter-width,0px)))] overflow-hidden animate-in fade-in zoom-in-95 duration-200",
+        'w-full max-w-[min(100%,calc(var(--oc-context-panel-width,100vw)-var(--oc-editor-gutter-width,0px)))] animate-in fade-in zoom-in-95 duration-200',
         className
       )}
       style={{
-        backgroundColor: currentTheme?.colors?.surface?.elevated,
-        borderColor: currentTheme?.colors?.interactive?.border,
         maxWidth: maxWidth ? `${Math.max(200, Math.floor(maxWidth))}px` : undefined,
       }}
       data-comment-input="true"
       onPointerDown={(e) => e.stopPropagation()}
       onTouchStart={(e) => e.stopPropagation()}
     >
-      <div className="p-3">
+      <div className="rounded-xl border border-[var(--interactive-border)] bg-[var(--surface-elevated)] shadow-[0_4px_16px_-4px_rgb(0_0_0_/_0.12)]">
-        {(fileLabel || lineRange) && (
+        {(fileLabel || displayRange) ? (
-          <div className="flex items-center gap-2 text-xs font-medium text-muted-foreground mb-2">
+          <div className="flex items-center gap-2 px-3 pt-2 text-xs font-medium text-[var(--surface-mutedForeground)] opacity-60">
-            {fileLabel && <span className="truncate max-w-[200px]">{fileLabel}</span>}
+            {fileLabel ? <span className="max-w-[200px] truncate">{fileLabel}</span> : null}
-            {fileLabel && lineRange && <span>•</span>}
+            {fileLabel && displayRange ? <span>•</span> : null}
-            {displayRange && (
+            {displayRange ? (
-              <span>
+              <span>{t('inlineComment.range.lines', { start: displayRange.start, end: displayRange.end })}</span>
-                {t('inlineComment.range.lines', { start: displayRange.start, end: displayRange.end })}
+            ) : null}
-              </span>
-            )}
           </div>
-        )}
+        ) : null}
-        
+        <div className="flex items-end gap-2 py-1 pl-3 pr-1">
-        <Textarea
+        <textarea
-          simple
           ref={textareaRef}
+          rows={1}
           value={text}
           onChange={(e) => handleTextChange(e.target.value)}
           onKeyDown={handleKeyDown}
           placeholder={isMobile ? t('inlineComment.input.placeholderShort') : t('inlineComment.input.placeholder')}
-          outerClassName="rounded-[var(--radius-xl)] bg-[var(--surface-subtle)] ring-1 ring-inset ring-border/60 focus-within:ring-2 focus-within:ring-[var(--interactive-focus-ring)]"
+          className={cn(
-          className="min-h-[80px] px-3 py-2.5 text-sm resize-y"
+            'min-w-0 flex-1 resize-none bg-transparent text-sm leading-5 text-[var(--surface-foreground)] outline-none placeholder:text-[var(--surface-mutedForeground)] placeholder:opacity-60',
+            isMobile ? 'py-1.5 text-base leading-6' : 'py-1.5'
+          )}
+          style={{ minHeight: 0, height: 'auto' }}
         />
-        
+        <button
-        <div className="flex items-center justify-end gap-2 mt-3">
+          type="button"
-          <Button
+          onClick={handleSaveClick}
-            variant="ghost"
+          onPointerDown={(e) => e.stopPropagation()}
-            size="sm"
+          onTouchStart={(e) => e.stopPropagation()}
-            onClick={onCancel}
+          disabled={!text.trim()}
-            onPointerDown={(e) => e.stopPropagation()}
+          className={cn(
-            onTouchStart={(e) => e.stopPropagation()}
+            'mb-0.5 flex shrink-0 items-center justify-center rounded-full bg-[var(--primary-base)] text-[var(--primary-foreground)] transition-opacity duration-150 hover:opacity-90 disabled:opacity-40',
-            className="h-8 text-muted-foreground hover:text-foreground"
+            isMobile ? 'h-9 w-9' : 'h-8 w-8'
-          >
+          )}
-            {t('inlineComment.actions.cancel')}
+          aria-label={t('inlineComment.actions.comment')}
-          </Button>
+          title={t('inlineComment.actions.comment')}
-          <Button
+        >
-            size="sm"
+          <Icon name="attachment-2" className="h-4 w-4" />
-            onClick={handleSaveClick}
+        </button>
-            onPointerDown={(e) => e.stopPropagation()}
-            onTouchStart={(e) => e.stopPropagation()}
-            disabled={!text.trim()}
-            className="h-8 min-w-[80px]"
-            style={{
-              backgroundColor: currentTheme?.colors?.status?.success,
-              color: currentTheme?.colors?.status?.successForeground,
-            }}
-          >
-            {isEditing ? t('inlineComment.actions.save') : t('inlineComment.actions.comment')}
-          </Button>
         </div>
       </div>
     </div>

packages/ui/src/components/views/PierreDiffViewer.tsx

@@ -82,6 +82,27 @@ const PIERRE_RUNTIME_BASE_CSS = `
 const WEBKIT_SCROLL_FIX_CSS = `
   ${PIERRE_RUNTIME_BASE_CSS}
 
+  /* While a multi-line content drag is being mapped to a line selection the
+     row highlight is the feedback; the native blue text selection on top of
+     it reads as double-selection, so it is painted transparent for the drag's
+     duration only (single-line selections keep the normal look for copying). */
+  :host([data-oc-comment-drag]) {
+    user-select: none;
+    -webkit-user-select: none;
+  }
+
+  /* Gutter "+" comment utility: theme primary, and smaller than Pierre's
+     1lh default, which reads oversized next to our 13px line numbers. */
+  [data-utility-button] {
+    width: 16px;
+    height: 16px;
+    align-self: center;
+    margin-right: calc(-16px + 1ch);
+    border-radius: 5px;
+    background-color: var(--primary-base);
+    color: var(--primary-foreground);
+  }
+
   :host {
     --diffs-bg-separator-override: var(--surface-elevated);
   }
@@ -598,6 +619,187 @@ export const PierreDiffViewer: React.FC<PierreDiffViewerProps> = ({
     }
   }, [setSelection]);
 
+  // Multi-line text selection over diff CONTENT highlights the same line
+  // range Pierre paints for number-column selection — without opening the
+  // comment editor. The "+" utility then targets the highlighted range.
+  const contentSelectionRef = useRef<SelectedLineRange | null>(null);
+  const contentSelectionClearTimerRef = useRef<number | null>(null);
+
+  useEffect(() => {
+    if (!enableComments) return;
+    const root = diffRootRef.current;
+    if (!root) return;
+
+    const getShadowRoot = (): ShadowRoot | null => {
+      const host = root.querySelector('diffs-container');
+      return host instanceof HTMLElement ? host.shadowRoot : null;
+    };
+
+    const setDragAttribute = (active: boolean) => {
+      const host = root.querySelector('diffs-container');
+      if (!(host instanceof HTMLElement)) return;
+      if (active) host.setAttribute('data-oc-comment-drag', '');
+      else host.removeAttribute('data-oc-comment-drag');
+    };
+
+    const lineFromPoint = (clientX: number, clientY: number): { line: number; side: AnnotationSide; numberColumn: boolean } | null => {
+      const shadowRoot = getShadowRoot();
+      const element = shadowRoot?.elementFromPoint(clientX, clientY) ?? document.elementFromPoint(clientX, clientY);
+      if (!(element instanceof Element)) return null;
+      const numberColumn = Boolean(element.closest('[data-column-number]'));
+      const row = element.closest('[data-line]');
+      if (!(row instanceof HTMLElement)) return null;
+      const line = Number.parseInt(row.getAttribute('data-line') ?? '', 10);
+      if (!Number.isFinite(line) || line <= 0) return null;
+      const side: AnnotationSide = row.getAttribute('data-line-type') === 'change-deletion'
+        || row.closest('[data-code][data-deletions]') != null
+        ? 'deletions'
+        : 'additions';
+      return { line, side, numberColumn };
+    };
+
+    let anchor: { line: number; side: AnnotationSide } | null = null;
+    let engaged = false;
+    let pointerId: number | null = null;
+
+    const highlight = (range: SelectedLineRange) => {
+      contentSelectionRef.current = range;
+      const instance = diffInstanceRef.current;
+      if (!instance) return;
+      try {
+        isApplyingSelectionRef.current = true;
+        instance.setSelectedLines(range);
+      } catch {
+        // ignore
+      } finally {
+        isApplyingSelectionRef.current = false;
+      }
+    };
+
+    const handlePointerDown = (event: PointerEvent) => {
+      if (event.button !== 0 || event.pointerType !== 'mouse') return;
+      const hit = lineFromPoint(event.clientX, event.clientY);
+      // Number-column drags belong to Pierre's own selection handling.
+      if (!hit || hit.numberColumn) {
+        anchor = null;
+        return;
+      }
+      anchor = { line: hit.line, side: hit.side };
+      engaged = false;
+      pointerId = event.pointerId;
+    };
+
+    const handlePointerMove = (event: PointerEvent) => {
+      if (anchor == null || event.pointerId !== pointerId) return;
+      const hit = lineFromPoint(event.clientX, event.clientY);
+      if (!hit) return;
+      if (!engaged) {
+        if (hit.line === anchor.line) return;
+        // The drag crossed into another line: from here it is a line
+        // selection, not a text selection. Drop the native selection and
+        // block new one from forming for the rest of the drag.
+        engaged = true;
+        setDragAttribute(true);
+        window.getSelection()?.removeAllRanges();
+        const shadowRoot = getShadowRoot();
+        if (shadowRoot && 'getSelection' in shadowRoot) {
+          // SAFETY: getSelection on ShadowRoot is a Chromium extension absent
+          // from lib.dom; the `in` check gates the call.
+          (shadowRoot as ShadowRoot & { getSelection: () => Selection | null }).getSelection()?.removeAllRanges();
+        }
+      }
+      highlight({
+        start: Math.min(anchor.line, hit.line),
+        end: Math.max(anchor.line, hit.line),
+        side: anchor.side,
+      });
+    };
+
+    const handlePointerUp = (event: PointerEvent) => {
+      if (anchor == null || event.pointerId !== pointerId) return;
+      const wasEngaged = engaged;
+      anchor = null;
+      engaged = false;
+      pointerId = null;
+      setDragAttribute(false);
+      if (!wasEngaged) return;
+      const range = contentSelectionRef.current;
+      contentSelectionRef.current = null;
+      if (!range) return;
+      // A half-written comment survives an accidental selection elsewhere.
+      if (selectionRef.current && commentTextRef.current.trim() && !editingDraftIdRef.current) return;
+      applySelection(range);
+      if (!editingDraftIdRef.current) {
+        setCommentText('');
+      }
+    };
+
+    root.addEventListener('pointerdown', handlePointerDown);
+    document.addEventListener('pointermove', handlePointerMove, { passive: true });
+    document.addEventListener('pointerup', handlePointerUp);
+    return () => {
+      root.removeEventListener('pointerdown', handlePointerDown);
+      document.removeEventListener('pointermove', handlePointerMove);
+      document.removeEventListener('pointerup', handlePointerUp);
+      setDragAttribute(false);
+    };
+  }, [applySelection, enableComments, setCommentText]);
+
+  // The gutter "+" utility: pressing it (or dragging from it) yields a line
+  // range; select it so the comment editor opens under the lines.
+  const handleGutterUtilityClick = useCallback((range: SelectedLineRange) => {
+    if (!enableComments) return;
+    // A content-drag highlight is the intended target when the pressed line
+    // falls inside it.
+    const highlighted = contentSelectionRef.current;
+    const withinHighlight = highlighted
+      && range.start >= highlighted.start
+      && range.end <= highlighted.end
+      && (range.side == null || range.side === highlighted.side);
+    if (contentSelectionClearTimerRef.current !== null) {
+      window.clearTimeout(contentSelectionClearTimerRef.current);
+      contentSelectionClearTimerRef.current = null;
+    }
+    contentSelectionRef.current = null;
+    applySelection(withinHighlight && highlighted ? highlighted : range);
+    if (!editingDraftIdRef.current) {
+      setCommentText('');
+    }
+  }, [applySelection, enableComments, setCommentText]);
+
+  // Clicking anywhere on a diff line (not only its number cell) toggles a
+  // single-line comment selection, matching the "+" utility's target.
+  const handleLineClick = useCallback((props: { lineNumber: number; annotationSide: AnnotationSide; numberColumn: boolean }) => {
+    if (!enableComments || props.numberColumn) return;
+    // Ignore when the user selected text on the way to this click (copying
+    // code must not pop the comment editor).
+    if (window.getSelection()?.toString().trim()) return;
+    const side: SelectedLineRange['side'] = props.annotationSide;
+    const range: SelectedLineRange = { start: props.lineNumber, end: props.lineNumber, side };
+    const current = selectionRef.current;
+    if (current && current.start === range.start && current.end === range.end && current.side === range.side) {
+      if (!commentTextRef.current.trim()) {
+        setSelection(null);
+        const instance = diffInstanceRef.current;
+        try {
+          isApplyingSelectionRef.current = true;
+          instance?.setSelectedLines(null);
+        } finally {
+          isApplyingSelectionRef.current = false;
+        }
+      }
+      return;
+    }
+    if (current && commentTextRef.current.trim() && !editingDraftIdRef.current) {
+      // A half-written comment survives an accidental click elsewhere.
+      return;
+    }
+    applySelection(range);
+    if (!editingDraftIdRef.current) {
+      setCommentText('');
+    }
+  }, [applySelection, enableComments, setCommentText, setSelection]);
+
   const resolveClickedSide = useCallback((numberCell: HTMLElement): AnnotationSide => {
     const lineType =
       numberCell.closest('[data-line-type]')?.getAttribute('data-line-type')
@@ -758,11 +960,13 @@ export const PierreDiffViewer: React.FC<PierreDiffViewerProps> = ({
     overflow: wrapLines ? ('wrap' as const) : ('scroll' as const),
     disableFileHeader: true,
     enableLineSelection: enableComments,
-    enableHoverUtility: false,
+    enableGutterUtility: enableComments,
+    onGutterUtilityClick: enableComments ? handleGutterUtilityClick : undefined,
+    onLineClick: enableComments ? handleLineClick : undefined,
     onLineSelected: enableComments ? handleSelectionChange : undefined,
     unsafeCSS: WEBKIT_SCROLL_FIX_CSS,
     renderAnnotation: enableComments ? renderAnnotation : undefined,
-  }), [darkTheme.metadata.id, enableComments, isDark, isLargeContent, lightTheme.metadata.id, renderSideBySide, wrapLines, handleSelectionChange, renderAnnotation]);
+  }), [darkTheme.metadata.id, enableComments, isDark, isLargeContent, lightTheme.metadata.id, renderSideBySide, wrapLines, handleSelectionChange, handleGutterUtilityClick, handleLineClick, renderAnnotation]);
 
 
   const lineAnnotations = useMemo(() => {