Allow icons and actions for (item) submenus

[itsmeipg]

I can't change the icon/add actions for items containing items, even though I can make them active.

[tomasklaen]

Actions don't show up for submenu buttons. They don't have values so the API wouldn't work, and action buttons would clash with submenu preview.

We could add values to submenus to support this, but I don't know what to do with the preview then, and overall I feel like this shouldn't be a thing.

[itsmeipg]

Oh okay that makes sense. Btw another small issue I have is action buttons not showing if selectable is false. Idk if I should open another issue (I made so many).

[tomasklaen]

Should they show up when selectable is false? Setting it to false implies the item is inactive, shouldn't be interacted with. It's used to make titles/separators. I wouldn't expect actions to show on those.

[itsmeipg]

I have a color menu that displays color properties with actions on the side to increase/decrease the values. Clicking the item does nothing so I think it should be unselectable. I think if an item is set to be unselectable, then it should be up to the menu creator to remove any existing actions (if they want).

Edit: Actually if I imagine it, it would look kinda weird tbh.