I'm seeing an issue w/ IE 10 (released w/ Win 8) and toolbar drop-downs. I'm using the latest build (Q2 '12 SP2) and it's also reproducible on Telerik's demo pages:
With drop-downs an IE 10, as the drop-down menu animated and is shown, the background <iframe> is visible in such a way that it is very noticeable as it covers the area that will be filled by the entire drop-down menu. This is visible for about 1/2 a second, depending on computer speed. To reproduce, go to the above link and click on the New menu. I've attached a screen shot that I took by manually hiding the <div> menu so you can see what I'm seeing for that 1/2 second of animation as the drop-down menu opens.
I was hoping that SP2 took care of all remaining IE 10 issues, but this is still present. Please advise and/or let me know if any of this is unclear.
- Mike Oliver