src/vs/workbench/contrib/terminal/browser/terminalTabsList.ts/TerminalTabList/_updateContextKey
class TerminalTabList:	private _updateContextKey() {
		this._terminalTabsSingleSelectedContextKey.set(this.getSelectedElements().length === 1);
		const instance = this.getFocusedElements();
		this._isSplitContextKey.set(instance.length > 0 && this._terminalGroupService.instanceIsSplit(instance[0]));
	}