src/vs/base/browser/ui/selectBox/selectBoxCustom.ts/SelectBoxList/onUpArrow
class SelectBoxList:	private onUpArrow(e: StandardKeyboardEvent): void {
		if (this.selected > 0) {
			dom.EventHelper.stop(e, true);
			// Skip disabled options
			const previousOptionDisabled = this.options[this.selected - 1].isDisabled;
			if (previousOptionDisabled && this.selected > 1) {
				this.selected -= 2;
			} else {
				this.selected--;
			}
			// Set focus/selection - only fire event when closing drop-down or on blur
			this.select(this.selected);
			this.selectList.setFocus([this.selected]);
			this.selectList.reveal(this.selectList.getFocus()[0]);
		}
	}