IE Tabsheet switching problem

I am not able to switch tabs (only in IE) which contains an embedded view for showing a pdf. It is working fine in all other browsers.
Kindly help.

I found the problem. I was using DDTabsheet instead of Tabsheet (from vaadin). The DDTabsheet (from drag drop layout) was used for enabling the dragging tabs. I was using

		mainTab.setDropHandler(new DefaultTabSheetDropHandler());

for enabling dragging/dropping. Once I commented these lines or removed DDTabsheet and used Tabsheet, it worked fine. The switching worked perfectly all right and also solved the problem in viewing of the pdf files in opera.
But still the requirement to drag/drop is open. Any one has any idea to implement this. Is there anything wrong with my implementation?