src/vs/base/browser/ui/selectBox/selectBoxCustom.ts/SelectBoxList/hideSelectDropDown
class SelectBoxList:	private hideSelectDropDown(focusSelect: boolean) {
		if (!this.contextViewProvider || !this._isVisible) {
			return;
		}

		this._isVisible = false;
		this.selectElement.setAttribute('aria-expanded', 'false');

		if (focusSelect) {
			this.selectElement.focus();
		}

		this.contextViewProvider.hideContextView();
	}