To be honest, i don't know what happened, it was working fine and now it doesn't i don't feel i have changed nothing.
I have the .desktop file in .local/share/launchers. Its code is:
[Desktop Entry] Type=Application Name=Matlab Comment=Matlab Exec=/usr/local/MATLAB/R2012a/bin/matlab -desktop Icon=/home/kais3r/.local/share/launchers/Matlab.png Terminal=false Categories=Math;IDE; StartupNotify=true
But i don't think the problem is related to this. Maybe some of the last updates? I don't know.
The point is that now, when i run matlab from its launcher a second icon will show up. Funny thing is that if i put the mouse on the new icon the text that appears onto it is not the one i have in my .desktop file, so my guess is that the launcher is launching the script but it is not capable of associating it with its icon, so it launches a secondary one.
So far it only happened with matlab. Any answer is welcome! Thanks!