src/vs/base/browser/ui/selectBox/selectBoxCustom.ts/SelectBoxList/constructSelectDropDown
class SelectBoxList:	private constructSelectDropDown(contextViewProvider: IContextViewProvider) {

		// SetUp ContextView container to hold select Dropdown
		this.contextViewProvider = contextViewProvider;
		this.selectDropDownContainer = dom.$('.monaco-select-box-dropdown-container');
		// Use custom CSS vars for padding calculation (shared with parent select)
		this.selectDropDownContainer.classList.add('monaco-select-box-dropdown-padding');

		// Setup container for select option details
		this.selectionDetailsPane = dom.append(this.selectDropDownContainer, $('.select-box-details-pane'));

		// Create span flex box item/div we can measure and control
		let widthControlOuterDiv = dom.append(this.selectDropDownContainer, $('.select-box-dropdown-container-width-control'));
		let widthControlInnerDiv = dom.append(widthControlOuterDiv, $('.width-control-div'));
		this.widthControlElement = document.createElement('span');
		this.widthControlElement.className = 'option-text-width-control';
		dom.append(widthControlInnerDiv, this.widthControlElement);

		// Always default to below position
		this._dropDownPosition = AnchorPosition.BELOW;

		// Inline stylesheet for themes
		this.styleElement = dom.createStyleSheet(this.selectDropDownContainer);
	}