This is the expected behavior - the minimized RadWIndow is still the active one - this is the last one the user interacted with, so it is shown on top. If you want another to become active you can do so in its OnCLientCommand event, e.g:
where $find("RadWindow1") is getting ar eference to the desired RadWindow. You can replace that with the one from your case or with a simple loop that goes through all windows in the manager;s collection and activates the first one that is already visible and is not the one we just minimized.
I can also suggest using the approach from this demo
to create an MDI-ilke interface.
Yet another alternative is using the MinimizeZoneID so it is minimized somewhere else on the page. Note that this is legacy functionality and may cause some issues in complex cases.
the Telerik team
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