triggerSubMenuAction also for submenu

[nuthinking]

In general, it makes sense to allow a menu to be initiated either by click or by hover. But general behavior is that submenus are open on hover. I would like, in fact, to have the menu initiated on click but the submenus on hover. Possible solution would be to expose triggerSubMenuAction also at submenu level.

[zhongzhong0505]

the same problem