Well for Unity/Ubuntu 16.04 I added a custom script to the quick launch menu by added a *.desktop file inside ~/.local/share/applications/
With content as:
[Desktop Entry]
Type=Application
Terminal=true
Name=pgadmin
Icon=/home/paul/pgadmin4/pgadmin4.png
Exec=/home/paul/pgadmin4/pgadmin4.sh
The contents of the script under /home/paul/pgadmin4/pgadmin4.sh are:
#!/bin/bash
cd ~/pgadmin4
source bin/activate
python3 lib/python3.6/site-packages/pgadmin4/pgAdmin4.py &
/opt/google/chrome/google-chrome --profile-directory=Default --app-id=ojglidlfoedmhkmjdapihkjneoemohjm &
(which launches pgadmin4 python + a webpage in chrome with the correct address).
However this no longer seems to work, I can (after some troubles, see comments) add the icon to the favourite bar and find the desktop entry when I search the applications. However trying to click this icon doesn't open anything, it seems the icon points to "nothing".
So how to actually make it execute the given script?