Cannot set custom command under "Open with..." context menu

On my system I have some chiptune music in form of .hvl files. These files cannot be played with standard media players so in the past I used this command to play files:

xfce4-terminal --geometry +450+300 --title "HVL Player" --command "aoss play_hvl %f"

This worked in the past without any problems. Now when I right click an hvl file and select "Open with-> Open with different application..." and in the dialog using the above command for the input field "Use a user defined command" and setting the checkbox "Use this by default for this file types" then nothing happens. The command won't be executed and there is also no added context menu entry something like "Open with terminal". It doesn't seem to be an issue with the command itself because that works when entering it to the command line directly.

What I found strange is when I click "file search..." in the "Open with different application..." dialog to search for the xfce4-terminal binary then the file isn't listed under /usr/bin when the filter in the file chooser dialog is set to "executable files" only. But this makes no sense because the executable bit is set. The file appears when the filter is set to "all files".

My system is Xubuntu 20.10 64 bit. I tested this with Thunar version 4.15.3 and 1.8.15.

Same issue as reported in #425 (closed)?

Seems so yeah. When I use double quotes at the beginning and the end for the above command without escaping anything then everything works fine:

"xfce4-terminal --geometry +450+300 --title "HVL Player" --command "aoss play_hvl %f""

Thank you for your help and sorry for this duplicate bug!

closed

added 3. Duplicate label