Remove Duplicate Icons In Show Applications
Solution 1:
After upgrade from Ubuntu Mate 19.04 to 20.04 I have received issue with double icons of network-manager in the tray.
According to answer of Kemin Zhou I have check my $HOME/.local/share/applications folder and I found there 3 files: mozo-made.desktop mozo-made-1.desktop mozo-made-2.desktop. I have removed files: mozo-made-1.desktop mozo-made-2.desktop and then rebooted the system and my issue with double netwok-manager icons was resolved.