I have tried to reproduce the unexpected behavior to open multiple RadWindows when the ViewState of the RadWindowManager is disabled, but to no avail. Could you please have a look at the short video in the attached archive and then tell me what I am missing?
Could you also try to reproduce the issue with the attached VS example and then tell me what changes you have made, so that I can make an investigation locally?
You can also put a flag that loads the RadWindow only on the first page load. For example:
Regarding the example, on how to open RadWindow from the server, you can find it in Opening RadWindow from the server
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