src/vs/workbench/contrib/extensions/browser/extensionsActions.ts/DropDownMenuActionViewItem/getActions
class DropDownMenuActionViewItem:	private getActions(menuActionGroups: IAction[][]): IAction[] {
		let actions: IAction[] = [];
		for (const menuActions of menuActionGroups) {
			actions = [...actions, ...menuActions, new Separator()];
		}
		return actions.length ? actions.slice(0, actions.length - 1) : actions;
	}