fix: table cell editor now closes on any other press on the unified canvas

[bvnaik05]

Summary

• Fixes Clicking empty canvas doesn't deselect an open table cell editor #563: with a table cell editor open (editingCell set), clicking empty canvas — away from the table — did not commit/close the editor on a unified document (the type "Create" makes, i.e. most new diagrams). The toolbar and caret both stayed on screen.
• Root cause: on the unified canvas, delegatesSurface() in DiagramCanvas.vue only routes a select-tool press to the whiteboard layer for tools in WHITEBOARD_TOOLS — select isn't one of them. So a plain empty-canvas click never reached the whiteboard's own selectAt/beginMarquee, which is what actually nulls editingCell and empties the selection on a miss-click. (A legacy whiteboard-only document was unaffected — there the sole-registrant rule routes every tool to the whiteboard layer regardless.)
• This is also the exact gap fix: table toolbar, header columns, click-to-select, wrap and auto-fit (#556) #557 documents as a deliberately-deferred "known gap" ("click-outside-deselect... unified documents"), so this closes that out too.
• Fix: onSurfacePointerDown now clears the whiteboard selection itself (whiteboardUi.clearSelection()) for a plain, non-additive press on a unified doc with the select tool, before routing the press onward — mirroring the same miss-click clear the legacy path already does. This closes the editor (committing the in-progress text) and drops the table's own selection, so clicking away returns the canvas to its normal, nothing-selected state.

Test plan

• yarn vitest run — all 151 files / 1741 tests pass, including a new tableCellEditorClose.test.js pinning the wiring (source-inspection house pattern — DiagramCanvas.vue can't mount in the node test env, same as structuralConnector.test.js)
• yarn build — succeeds
• Manually verified in the running app on a unified document: opened a table cell (double-click), typed text, clicked empty canvas — the text committed, the cell-editing toolbar disappeared, and the table's own selection cleared too (toolbar reverted to the plain Select state)

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[greptile-apps]

Confidence Score: 4/5

The mixed-selection drag regression should be fixed before merging because dragging a selected shared shape leaves co-selected whiteboard objects behind.

The unconditional pre-routing clear removes whiteboard objects before the shared transform captures the complete mixed selection.

Files Needing Attention: frontend/src/components/canvas/DiagramCanvas.vue

Prompt To Fix All With AI

### Issue 1
frontend/src/components/canvas/DiagramCanvas.vue:509
**Mixed selection drag breaks**

When a unified canvas has a shared shape and whiteboard object selected together, this clears the whiteboard selection before the shared move snapshots it, causing the shape to move while the co-selected whiteboard object stays behind.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "fix: table cell editor now closes on any..." | Re-trigger Greptile}

[greptile-apps]

Mixed selection drag breaks

When a unified canvas has a shared shape and whiteboard object selected together, this clears the whiteboard selection before the shared move snapshots it, causing the shape to move while the co-selected whiteboard object stays behind.

Knowledge Base Used:

• Canvas interaction and rendering
• Whiteboard and freeform content

Prompt To Fix With AI

This is a comment left during a code review.
Path: frontend/src/components/canvas/DiagramCanvas.vue
Line: 509

Comment:
**Mixed selection drag breaks**

When a unified canvas has a shared shape and whiteboard object selected together, this clears the whiteboard selection before the shared move snapshots it, causing the shape to move while the co-selected whiteboard object stays behind.

**Knowledge Base Used:**
- [Canvas interaction and rendering](https://app.greptile.com/frappe/-/custom-context/knowledge-base/frappe/draw/-/docs/canvas-interaction-and-rendering.md)
- [Whiteboard and freeform content](https://app.greptile.com/frappe/-/custom-context/knowledge-base/frappe/draw/-/docs/whiteboard-and-freeform-content.md)

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

[vibhavkatre]

The diagnosis is right and the placement in onSurfacePointerDown is right, but one claim in the new comment is not true, and because of it the fix leaves a table on the unified canvas with no way back.

The comment says the press can never be on the table:

A press that reaches this handler is always off the table (its own pointerdown intercepts and stops propagation for any in-bounds press)

WhiteboardTable.vue:185 only stops propagation once the table is already selected:

if (isAdditiveEvent(event) || !ui.isSelected('table', props.table.id)) return
event.stopPropagation()

and the comment above it says so explicitly — "fall through to the surface selectAt". On a legacy whiteboard that fall-through lands in selectAt, which selects the table. On a unified document it lands here, and delegatesSurface() returns false for the select tool, so nothing selects it.

What that costs. Today the only route into a table on a unified canvas is editTableCellAt on double-click (DiagramCanvas.vue:632), which selects the table and opens a cell editor. Before this PR the selection then stuck around — the bug #563 reports — so the table stayed usable. After this PR, clicking empty canvas correctly deselects it, and a single click on the table no longer brings it back: the user has to double-click into a cell every time they want to move or restyle the table.

The fix is small and belongs in the same block. Export a selectWhiteboardAt(store, point) from useWhiteboardInteraction.js — whiteboardHitAt + SELECT_FN are already there, just not exported — and in onSurfacePointerDown select the object under the point if there is one, clear otherwise:

if (isUnified.value && editorUi.state.tool === 'select' && !isAdditiveEvent(event)) {
  const point = selection.toLogicalFor(event, surface.value, viewport)
  if (!selectWhiteboardAt(store, point)) whiteboardUi.clearSelection()
}

That keeps everything #563 asks for, makes a table selectable by a plain click on the unified canvas the way it is on a legacy whiteboard, and — worth checking while you are there — probably closes the same gap for drawn lines and strokes, which have no per-object pointerdown at all.

On the test. The source-inspection pattern is the house one and fine here, but the first regex pins the exact whitespace and line breaks of the if, so reformatting the condition breaks a passing test for no reason. The three ordering assertions below it are the ones carrying real meaning; I would keep those and loosen the first to the parts that matter (isUnified, tool === 'select', !isAdditiveEvent, clearSelection).