src/vs/base/browser/ui/tree/abstractTree.ts/FindController/close
class FindController:	close(): void {
		if (!this.widget) {
			return;
		}

		this.widget = undefined;

		this.enabledDisposables.dispose();
		this.enabledDisposables = new DisposableStore();

		this.previousPattern = this.pattern;
		this.onDidChangeValue('');
		this.tree.domFocus();

		this._onDidChangeOpenState.fire(false);
	}