Consider a scenario with two Windows. The first one is centered. Users open a second Window from the first one, and the second Window gains focus.

At this point, if the user clicks on the titlebar of the first Window, it will lose its centered position and move to the corner of the screen.

Here is a REPL test page: https://blazorrepl.telerik.com/wSOMEtEL55Ddk4v441

A possible workaround is to set explicit Width, Height, Top and Left values to the first Window, so that it's not centered, but appears to be: https://blazorrepl.telerik.com/QeaWuNus07TfnCz731