fix: memory leak in modalEditorPart

[Simon Siefke (SimonSiefke)]

Details

When opening a modal like the new images preview, a memento seems to be created. But when closing the modal, the memento seems to be not removed.

Change

This changes it so that there is only one global memento for modals, instead of one per modal. This ensures no extra mementos are created when opening and closing a modal.

My understanding is that modalEditorPart doesn't need a memento at all, since it doesn't save any state:

protected override saveState(): void {
	return; // disabled, modal editor part state is not persisted
}

Before

When opening and closing the images modal 37 times, the number of ScopedMemento objects seems to grow by 1 each time:

After

No more leak is detected.

Test Video

video-edited-2.mp4

[vs-code-engineering]

📬 CODENOTIFY

The following users are being notified based on files changed in this PR:

Benjamin Christopher Simmonds (@benibenj)

Matched files:

• src/vs/workbench/browser/parts/editor/modalEditorPart.ts

[Copilot]

Pull request overview

Prevents modal editor recreation from growing the global memento cache.

Changes:

• Replaces per-instance IDs with a stable modal editor component ID.
• Removes the modal instance counter.

[Dmitriy Vasyura (dmitrivMS)]

Simon Siefke (@SimonSiefke) Thank you!