How can I change submenu alignment?

Hi,

I want to display a button menu to the top right of my window.
That menu contain a submenu, and unfortunately submenu items are partially hidden by the end of the window.

I want to change the direction of submenu items. Changing the alignment only change the inner text alignment, but not the item itself.

How can I change the submenu alignment?

PS: I'm working on ThingWorx 7.3.3

Regards