Empty module tab when adding a product

[TR7]

Hi!

Unfortunately I have a problem with the modules tab when adding/editing products. Instead of displaying the modules to choose from, the tab does not display anything.

I have an older copy of the shop and there the modules are displayed correctly. I tried uninstalling the newly added modules from the original shop - unfortunately this did not help. 

I also can't transfer the copy of the shop to the original, because the copy is too old and too many changes have been made to the original shop.

Unfortunately I don't know how to deal with this problem anymore.

Thank you

 

Edited September 12 by TR7 (see edit history)