src/vs/workbench/api/common/extHostQuickOpen.ts/ExtHostQuickOpenImpl/$onDidChangeActive
class ExtHostQuickOpenImpl:		$onDidChangeActive(sessionId: number, handles: number[]): void {
			const session = this._sessions.get(sessionId);
			if (session instanceof ExtHostQuickPick) {
				session._fireDidChangeActive(handles);
			}
		}