Drag and Drop no longer working
Apologies, this should be in the 3.x Forum.
Could you create a new clean master page and then create a page though Sitefinity based on this template and see if the issue appears. Inside your template or page do not add controls, references, scripts etc.
- check if the issue is browser related
- make sure that your dlls are built against the same version that your app pool runs.
the Telerik team