As I understand your setup, your RadGrid and RadWIndow are inside an IFRAME and you want to display RadWindow on the topmost page, e.g. outside of the IFRAME. If this is your setup, this is not possible - RadWindow, just like any other DHTML element can exist only in the page in which it is created. If you want to show a RadWindow on your topmost page you need to declare it there and open it from inside the IFRAME - for example by using top.radopen().
All the best,
the Telerik team
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