I have just upgraded from ZorinOS 15.3 Premium to 16 Pro. With 15.3, I created .desktop files for apps I developed. I placed them in ~/.local/share/applications. They then appeared under 'Other' in the start menu and worked as desired. I also placed them on the taskbar. With ZorinOS 16 they are not appearing, although the .desktop files are still there. As a test, I copied one of them to /usr/share/applications. It made no difference. Following are the contents of one of the previously working files. Note that my apps appeared under 'Other' in 15.3 rather than under 'Jim' as I specified (apparently incorrectly).