I never had this exception before. And it's really hard to debug.
I use a JumpList to display a large collection of entries in a Panorama control on Windows Phone 7. I am using the last stable release of the Phone components, and tried already the internal build as well.
The problem occurs, when I navigate to another page, and return to Main.xaml which contains the Panorama control. When I remove the PanoramaItem that contains the JumpList, the error does not occur.
Please let me know, what further Informations you need, because I really want to release that project in the next few days :)
Thank you very much.
Update: I read this thread here on SO and will check my solution: http://stackoverflow.com/questions/636245/silverlight-error-layout-cycle-detected-layout-could-not-complete-when-using-c
But please let me know, if you need further information's.
UPDATE: I can ignore the Exception, but it will give me a black screen when I switch back to Main.xaml for about half of a second. Not sexy but until the error is nailed - solution. And I am unable to get the stack trace of the exception, so I assume, that it occurs somewhere inside your control.