I think I found a solution for ALL missing icons to programs in the main menus that should be there.
I don't have a LL machine here to try but I found something really interesting here :
https://bugs.launchpad.net/ubuntu/+sourc...ug/1332385
and a great explanation at comment number 8 (
https://bugs.launchpad.net/ubuntu/+sourc...comments/8)
Gisin Bernard (bernard5) wrote on 2014-08-24:
The bug described by ToZ comes from a more general Bug.
In Xfce, if a menu contains only submenues, this menu is not visible.
Using the "menu principal" in french or "Main menu", from the "alacarte" package, you can add a "new item" to the menu, then the menu will be visible.
For example, if you add any "new item" to the "Programs" menu of "Wine", then the "Programs" menu of "Wine" will be visible.
Il you remove all "item" from the "Programs" menu, it will disapear.
The same is true for any other menu, having only "submenus" without any items.
You can try adding a submenu to "System", it will not appear until you add an item to this submenu.
Temporarly, a way to deal with this bug is to add any "new item" to a menu, to make it appear.
This was tested with XUbuntu 14.04, on different computers and different installations.
I tested also that this bug doesn't exist under KDE and GOME, but exist under XUbuntu and under Xfce.
+ other comments mentionned that sames goes for Xubuntu 16.04 and 17.04.