src/vs/workbench/api/browser/mainThreadDocumentsAndEditors.ts/MainThreadDocumentAndEditorStateComputer/_onDidRemoveEditor
class MainThreadDocumentAndEditorStateComputer:	private _onDidRemoveEditor(e: ICodeEditor): void {
		const id = e.getId();
		if (this._toDisposeOnEditorRemove.has(id)) {
			this._toDisposeOnEditorRemove.deleteAndDispose(id);
			this._updateState();
		}
	}