20.04 : "open with other application" menu not working properly on the Desktop

I recently installed 20.04 and for some kinds of files, whether text or binary ones, I'm unable to choose an application to open them like I used to in 18.04.

For example, when I right-click a .c (C source code) file and select 'open with other application', it immediately opens it with gedit, even though I have other programs able to open these, like Geany.

For other kind of files, like object code/ binary files, the menu does show up but it says there are "No Apps Available" for it, whereas I have several programs able to read them, like GHex. Even worse, double clicking on these files has no effect. In 18.04 it would at least try to open them with gedit.

The .desktop files in /usr/share/applications have the correct Exec=command %F, so I have no idea why it doesn't list them.

What's even stranger is that for some filetypes like images, the menu works fine and even has the View all applications button, which is the behavior I wish to have for ALL files, regardless of their extensions and MIME type.

Is there a way to force Gnome to list all possibilities when I click on "open with other applications" ?

Thanks for your tips !

Edit : I've narrowed down the bug behavior : it only happens on the Desktop. When opening files through Nautilus, the correct behavior happens.

In case my description is not clear, here are images showing the desired and problematic behaviors of the "Open With other application" menu :

Solution 1:

Ubuntu 20.04 uses a Gnome Shell extension to handle files on the desktop, whereas previously, these files were handled by the file explorer, nautilus. This extension is limited and has several limitations, including lacking the ability to assign applications to a file type. So, until that extension is further developed, you have to use the file manager.