Show loading dialog / Set try-catch

[maiko3tattun]

Improvements:

• Show dialog when heavy processing
• Set try-catch for some processes to avoid crashes

[maiko3tattun]

bandicam.2023-10-20.23-04-47-796.mp4

[stakira]

This is a nice change, but I don't think it should be done with a notification. As you have found, I'd prefer a message box modal created and destroyed locally like in RegenFrq().

[maiko3tattun]

This may be called from the ViewModel, so they cannot find the parent window...