Hi,

We have investigate the reported issue further and we have found that it is actually caused by the Framework itself when DisableDpiAwareness is used. The same behavior can be observed if the native WPF Window is used instead RadWindow.

Both the native Window and RadWindow are not DPI aware when the DPI is changed due the set DisableDpiAwareness. If you want RadWindow be aware of the DPI changes when it minimizes you need to implement some custom logic. Please, check the link below that provides very detailed information how the native Window could become responsive of DPI changes when DisableDpiAwareness  is set in the AssemblyInfo - the same approach could be used for RadWindow:
https://msdn.microsoft.com/en-us/library/windows/desktop/ee308410(v=vs.85).aspx

Using the described in MSDN approach RadWindow will behave as expected when it is Minimized. We have applied the approach for RadWindow and attached you can find a sample project that demonstrates how it works.

We hope this information will be helpful.

Regards, 
Nasko