src/vs/platform/theme/common/styler.ts/attachSelectBoxStyler
export function attachSelectBoxStyler(widget: IThemable, themeService: IThemeService, style?: ISelectBoxStyleOverrides): IDisposable {
	return attachStyler(themeService, {
		selectBackground: style?.selectBackground || selectBackground,
		selectListBackground: style?.selectListBackground || selectListBackground,
		selectForeground: style?.selectForeground || selectForeground,
		decoratorRightForeground: style?.pickerGroupForeground || pickerGroupForeground,
		selectBorder: style?.selectBorder || selectBorder,
		focusBorder: style?.focusBorder || focusBorder,
		listFocusBackground: style?.listFocusBackground || quickInputListFocusBackground,
		listInactiveSelectionIconForeground: style?.listInactiveSelectionIconForeground || quickInputListFocusIconForeground,
		listFocusForeground: style?.listFocusForeground || quickInputListFocusForeground,
		listFocusOutline: style?.listFocusOutline || ((theme: IColorTheme) => theme.type === ColorScheme.HIGH_CONTRAST ? activeContrastBorder : Color.transparent),
		listHoverBackground: style?.listHoverBackground || listHoverBackground,
		listHoverForeground: style?.listHoverForeground || listHoverForeground,
		listHoverOutline: style?.listFocusOutline || activeContrastBorder,
		selectListBorder: style?.selectListBorder || editorWidgetBorder
	} as ISelectBoxStyleOverrides, widget);
}