When I try to edit the content of panels pages, I click the add content link in the drop down menu an drag and drop down menu. The progress indicator appears and turns for a while and then nothing happens. The screen remains with the semi transparent overlay (screenshot below).
Also, drag and drop for reordering the content does not work.
Assuming it is related with an ajax call I checked the chrome console but there seems to be no error.
I am using: panels 7.x-3.3 ctools 7.x-1.3 jQuery v1.8.3 jQuery UI 1.8.7 jQuery UI Draggable 1.8.7 jQuery UI Droppable 1.8.7
I have been searching for hours now but could not find a related post anywhere.
(a note: I do not have firebug or facebook modules installed. they are reported to cause a similar problem)