Comment 7 for bug 1873428

Ok - you are referring to 20.04. The default appmenu is the grid/list view menu - not the classic budgie desktop menu.

The Alt+F2 pop-up is from budgie-desktop.

Your issue is this: https://github.com/elementary/applications-menu/issues/53#issuecomment-524092049

Its a GLIB issue - with no real resolution. Adding xterm is a workaround, but its not something we will be doing out of the box since having multiple terminal's in the menu is confusing.

We could in theory hard-code something for UB's tilix terminal for the menu but that will break other distros.

I'll add the issue to the 20.04 release notes but there isn't anything we can readily do here.