src/vs/workbench/browser/parts/editor/textDiffEditor.ts/TextDiffEditor/scopedContextKeyService
class TextDiffEditor:	override get scopedContextKeyService(): IContextKeyService | undefined {
		const control = this.getControl();
		if (!control) {
			return undefined;
		}

		const originalEditor = control.getOriginalEditor();
		const modifiedEditor = control.getModifiedEditor();

		return (originalEditor.hasTextFocus() ? originalEditor : modifiedEditor).invokeWithinContext(accessor => accessor.get(IContextKeyService));
	}