In GF 1.6.2 the form editor breaks down when using the Dutch localization file. It narrows down to "Form Settings", the rest still works.
If I remove the mo-file from the languages-folder, the problem is gone.
There is a js-error which might help you:
Uncaught ReferenceError: FieldClick is not defined
There is one more detail. I'm running AgentPress 2.0 from StudioPress and several plugins they advice (like GF). The strange thing is that the error is also gone when using the Dutch localization and switching off the AgentPress Listings-plugin or the jQuery Lightbox For Native Galleries-plugin.
That made me think there was some conflict with AgentPress and GF, and StudioPress' support did look into it, but couldn't find a problem.
And seeing how it all works properly when turning off the localization for GF, I thought this was the right place to address this issue next.
Hope you can help me :)