I built UE5 from source for linux, and generally it works well, however whenever I expose a menu such as the ‘File’ menu or a left click menu, I find if I mouse over ‘too quickly’ the menu will close on me. It seems what happens is the editor notices my mouse over a menu entry, and exposes a submenu, but then next it checks, my mouse has moved much farther away (but still on the menu) and it thinks I moused away, and then closes the menu. It’s very frustrating, but I can get around it by slowly mousing along the menu to get the item I want or use a keyboard shortcut.
I’m running Arch Linux with XFCE desktop manager.