Hello.
I use Paint.net only to edit graphic files, I use another program for viewing graphic files.
Therefore, I do not choose "always use this program" for Paint.net to open these graphic files.
With Paint.net 4 for open graphic files im use this - first time - right click on jpg file, choose "open with", find exe file of Paint.net through the file manager, and NOT choose "always use this application", click "Ok" - then jpg file open in Paint.net 4. AND when the next time I press the right mouse button on the jpg file, choose "open with", then there is already a program Paint.net, It is not necessary to look for it through the file manager again.
But with Paint.net 5 and Paint.net 5.02 This does not happen - "when the next time I press the right mouse button on the jpg file, choose "open with", then there is already a program Paint.net", There is no Paint.net in this menu, It is NECESSARY to look for program Paint.net through the file manager every time.
How fix it? Windows 10, 64bit.
If I install Paint.net version 4 again, then the problem disappears, the program Paint.net is added as I wrote above to the "Open with" menu.