Different behavior when launched from terminal instead of Unity launcher

Question

I have written two Perl/Gtk programs. When launched from the dash menu, they run just fine.

However, if I try to launch them from terminal using the very same command found in their .desktop files, their Unity launcher will be blurry and will remain inactive when clicked, if I keep it in the Unity bar.

The problem is solved if the Exec part of the desktop file is replaced with

perl path_to_script

However, that leads to other problems, including a lintian warning and forcing all Perl GUI applications running from terminal to adopt the same launcher.

This issue is quite annoying since one of the programs relies on a different (Python) program in order to be launched and this results in having a blurry and inactive launcher.

Answer 1

I found out what was wrong. I had to enter the correct StartupWMClass at the .desktop file.

For those who are struggling with it, launch the application from terminal and execute in a different terminal the command

xprop | grep WM_CLASS

Click on your application and the output of the previous command will be

WM_CLASS(STRING) = "result"

Add to the .desktop file the following line:

StartupWMClass=result

Substitute result with your output.