The XFCE menu is huge, it seems to contain an exhaustive list of possible applications, most of them are not on my system. This includes
lots of things from other desktops such as KCompare, KWrite, etc.

Is there a way to have the menu regenerated to include only applications that are actually installed?

Otherwise, it would be more tedious, but is there a way to edit the menu?

A long time ago I was using Gnome and it had a menu editor built-in, is there something similar for XFCE?