You can Pin the RadWindow so it stays in place when scrolled. This is easiest done with the following line:
and this can be executed in the OnClientShow event, for example, to have it always pinned. In the above line oWnd is a reference to the RadWindow object; in case you call it in a handler for one of its client-side events you can use the first argument the handler receives.
All the best,
the Telerik team
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