fix(context-menu): paste via context menu inserts at wrong position (SD-1302)

[tupizz]

The Bug

Pasting via the right-click context menu inserts content at the beginning of the document instead of at the cursor position.

Steps to reproduce:

1. Type a sentence, press Enter a few times to create empty paragraphs
2. Select a word → right-click → Copy
3. Click on an empty paragraph below → right-click → Paste
4. The word appears at position 0 (top of the document) instead of where the cursor was

Copy, Cut, and Ctrl+V all work correctly — only context-menu Paste is broken.

Root Cause

The paste action in menuItems.js called view.dom.focus() (raw DOM focus) before reading the clipboard. This is subtly different from view.focus() (ProseMirror-aware focus), and the difference is the root cause:

What view.dom.focus() does (broken)

1. Focuses the contenteditable DOM element
2. Triggers ProseMirror's internal `handlers.focus` callback
3. handlers.focus restarts the DOMObserver immediately
4. DOMObserver reads the current browser selection — which is stale
   (collapsed at document start, because the context menu's hidden
   search input had focus, not the editor)
5. DOMObserver overwrites ProseMirror's selection state with position 0
6. The async readClipboardRaw() completes, but selection is now at 0
7. Content gets pasted at position 0

What view.focus() does (correct)

1. Stops the DOMObserver first
2. Focuses the contenteditable DOM element
3. Writes ProseMirror's selection TO the DOM (selectionToDOM)
4. Only then restarts the DOMObserver
→ The observer sees the correct selection, no corruption

The key insight is that when the context menu is open, its hidden search input holds browser focus. The browser's native selection drifts to position 0. Raw dom.focus() lets the DOMObserver read this stale position before ProseMirror can sync its own selection back to the DOM.

Copy and Cut don't have this problem because they already use editor.focus() → view.focus() (PM-aware) and are synchronous (no async gap).

The Fix

Two changes, both in the paste action inside menuItems.js:

1. Use view.focus() instead of view.dom.focus()

This prevents the DOMObserver from reading a stale selection during focus.

2. Save/restore selection across the async clipboard read

Even with view.focus(), there's an async gap during await readClipboardRaw() where the DOMObserver could still corrupt the selection (e.g., if the browser fires another focus/blur cycle). As a safety net:

// Save before focus
const savedFrom = view.state.selection.from;
const savedTo = view.state.selection.to;

view.focus();
const { html, text } = await readClipboardRaw();

// Restore after async gap
if (view.state?.doc?.content) {
  const { tr, doc } = view.state;
  const maxPos = doc.content.size;
  const safeFrom = Math.min(savedFrom, maxPos);
  const safeTo = Math.min(savedTo, maxPos);
  const SelectionType = view.state.selection.constructor;
  if (typeof SelectionType.create === 'function') {
    view.dispatch(tr.setSelection(SelectionType.create(doc, safeFrom, safeTo)));
  }
}

The Math.min clamping handles edge cases where the document might shrink during the async gap (e.g., a collaboration update arrives mid-paste). The defensive guards (doc.content check, typeof create === 'function') ensure graceful degradation in environments with incomplete mock/state objects.

Why This Approach

• Minimal change — only touches the paste action, no architectural changes
• Matches copy/cut pattern — Copy and Cut already use editor.focus() / view.focus(), this aligns Paste with the same pattern
• Defense in depth — view.focus() fixes the primary issue, save/restore handles async edge cases
• Safe for collaboration — position clamping prevents RangeError if the document changes during the async clipboard read

Tests

7 new unit tests covering:

• view.focus() is called instead of view.dom.focus()
• Selection is saved before focus and restored after clipboard read
• Position clamping when document shrinks during async gap
• Graceful behavior when doc.content or SelectionType.create is unavailable
• Collapsed cursor (from === to) is restored correctly
• Selection is restored before handleClipboardPaste runs

All 666 test files / 6235 tests pass.

Manual Test Plan

• Type text, press Enter a few times, select a word → right-click → Copy → click below → right-click → Paste → content appears at cursor
• Ctrl+V paste still works correctly
• Context menu Cut still works
• Context menu Copy still works
• Paste with HTML content (copy from external app) works at correct position

[linear]

SD-1302 Bug: Paste via context menu does not work

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[Copilot]

Pull request overview

Fixes a ProseMirror context-menu paste bug where pasted content was inserted at the start of the document by ensuring focus/selection is preserved correctly during the async clipboard read.

Changes:

• Switches paste action focusing from raw DOM focus (view.dom.focus()) to ProseMirror-aware focus (view.focus()).
• Saves the current ProseMirror selection before reading from the clipboard and attempts to restore it after the async clipboard read gap.

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[harbournick]

LGTM

[superdoc-bot]

🎉 This PR is included in superdoc v1.15.1-next.1

The release is available on GitHub release