I have problem on Form Editing. Serialized Json appears on Form Editor screen, It makes form editing not working including drag drop, add new fields, etc.
Here is the screenshot: http://screencast.com/t/fRg4Piga
The issue is not occured on new form creation.
Actions taken but not solve the problem:
1. Deactivate and Re-activate the GF plugin.
2.Deactivate and Re-activate other plugins not solving the problem either.