The part of the code that you posted looks good and should not be the reason for the problem. Is the radWindow1 window already visible?
If you want to show a RadWindow from the server, note that it has to have its VisibleOnPageLoad property set to true.
As for your second question, I suggest to use the client-side API (moveTo() method) to position the RadWindow.
If you continue to experience problems with your scenario, please open a support ticket and send us a small sample project that illustrates them. We will check it right away.
the Telerik team
, the state of the art learning tool for Telerik products.