Commented Issue: CommandManager.InvalidateRequerySuggested Ignored [300]

The command guards (properties and methods) do not get rechecked when CommandManager.InvalidateRequerySuggested() is invoked; they really should do.
Comments: Actions do not use the ICommand infrastructure, so InvalidateRequerySuggested is meaningless. You need to signal a property changed on the guard, or provide proper parameters to the guard method to male it update.