Weird Widget Problem

Hello

My site is running fine. However, lately I am witnessing this:

Whenever I try to add ANY widget, after putting, the cursor remains at “four-arrows”. I mean the cursor does not return to normal pointer. If I refresh the widget page, the newly put widget is gone.

Normally, when you place a text widget, the text box opens up allowing us to put a heading & content. Here the dragged widget “just” stays there, nothing happens further. This happens with every widget I drag to the RHS.

I am using Maxima from TF. Developer says its WP problem.

See here

Any ideas? Thanks in advance.