Scope EditorTabsVisibleContext to editor parts for correct action resolution

[bpasero]

When the modal editor part enforces showTabs: 'multiple' (or 'none'), the EditorTabsVisibleContext was only set globally based on the main editor part's options. This caused close/unpin actions gated on EditorTabsVisibleContext.toNegated() to incorrectly appear in the modal editor when the user had tabs configured as 'single' globally.

Fix: Bind EditorTabsVisibleContext to EditorPart.scopedContextKeyService in handleContextKeys(), matching the existing pattern for EditorPartMultipleEditorGroupsContext and EditorPartMaximizedEditorGroupContext. The scoped value overrides the global one within each editor part's DOM subtree, so actions resolve correctly against the enforced options.

Consumers of this context key (all in editor.contribution.ts):

• Close button (normal/dirty editor) — when: EditorTabsVisibleContext.toNegated()
• Unpin button (sticky/dirty+sticky) — when: EditorTabsVisibleContext.toNegated()
• "Close to the Right" context menu — when: EditorTabsVisibleContext

[Copilot]

Pull request overview

This PR fixes incorrect action visibility in the modal editor by scoping EditorTabsVisibleContext to each EditorPart's own scopedContextKeyService, rather than relying solely on the global context key derived from the main editor part. Without this fix, when the modal editor enforces showTabs: 'none' or 'single', actions gated on EditorTabsVisibleContext.toNegated() (e.g. close/unpin buttons in the title bar) would resolve incorrectly because the global key still reflected the main window's tab setting.

Changes:

• Bind EditorTabsVisibleContext to EditorPart.scopedContextKeyService in handleContextKeys(), matching the existing pattern for EditorPartMultipleEditorGroupsContext and EditorPartMaximizedEditorGroupContext.
• Add a listener on onDidChangeEditorPartOptions to keep the per-part scoped value in sync when options change (including enforced overrides).
• Add a test in editorGroupsService.test.ts to verify the scoped context key correctly reflects enforced showTabs values.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/vs/workbench/browser/parts/editor/editorPart.ts	Adds scoped binding + listener for EditorTabsVisibleContext in handleContextKeys()
src/vs/workbench/services/editor/test/browser/editorGroupsService.test.ts	New test verifying context key updates with enforced showTabs values