Habpanel JSON Import Error

I need to add a bunch of buttons to my habpanel design.

As there are hundreds of them (I use them to select all my music albums) tt’s easier for me to do that directly in the JSON file.

The problem is that as soon as I add a new button widget it creates an error when I try to import the new JSON file in Habpanel.

I could JSON edit existing widget content without any problem but as soon as I add or remove a widget it shows an error “Problème pendant l’import : SyntaxError: Unexpected token } in JSON at position 750” regardless of the fact that the {} that I can see are all correct.

Any solution to that JSON editing problem?