Mouse Cursor not hidden in XAML based apps.

In xaml, mouse must be actively turn off during initialization.
Seting Game.IsMouseVisible =false; has no effect because the code check
against current value, which is by default false;
Now, In order to hide the mouse cursor one must do
IsMouseVisible = true;
IsMouseVisible = false;

Another thing: The execution path through
MetroGamePlatform.RunLoop()
MetroGameWindow.RunLoop()
which call SetCursor(false), doesn't seem to be active anymore.