There should be an option like the actual "can fade" setting in the channel settings to choose if a channel is affected by the grand master and submasters. At the moment the situation is not ideal mainly because of two reasons:
- A RGB fixture with explicit master dimmer channel is dimmed down twice as fast as a 3 channel RGB fixture.
- Color fades aren't smooth any more if a submaster is dimmed down because it also ducks the RGB values and so there are less values to fade.
To make this feature perfect it would be good to have a default value in the fixture definition. Maybe that would be a good idea for the "can fade" setting, too.