Hi Frank,
You need to set a higher z-index to the RadWindowManager. More information on the subject is available here:
http://www.telerik.com/support/kb/aspnet-ajax/window/show-radwindow-above-radmenu.aspx
http://www.telerik.com/help/aspnet-ajax/controlling-absolute-positioning-with-zindex.html
As for the second problem, could you please provide some more details on it? I am not quite sure if I understand you correctly.
Greetings,
Georgi Tunev
the Telerik team