Hookpad is a great tool for trying out different ideas quickly! However I have an issue with some slash chords.
For example: In case the song is in Eb major, how do I input Ab maj7 / Bb chord?
Inverted suspended chords aren't allowed unless you go hacking into the client files themselves. There were some forks that people used to do this sort of thing but they aren't native to the application for an end user to invoke.