OK. I see the issue now.
Messy.
The only workaround that seems available is not to use a mask, and use TextChange instead.
[quote=265391:@Michel Bujardet]OK. I see the issue now.
Messy.
The only workaround that seems available is not to use a mask, and use TextChange instead.[/quote]
Yes sir. I am using TextChange now instead of masks
For capital letters on TextChange:
me.text = Uppercase(me.text)
me.SelStart=len(me.Text)
For my other mask I had to get a little creative but did it all with code instead of Masks.
My problem is solved by not using Masks 
The other solution I can think of is to use mask, and in keydown to manage Ctrl-X, C, V through the Xojo Clipboard and return true for all control characters when Keyboard.AsyncKeydown, so no strange characters can be entered.
Whatever works best.
I do hope Xojo fixes the bug, though.