Combo classes are really an ugly approach. Every time you need to change something in the basic class you have to click back and forth, you need to remember to add the combo class on new elements, it’s really a mess.
I can’t get the rationale behind sticking to the use of combo classes. I use them only as a last resort and think this is what they are for - usage only in isolated cases. I’ve gone through the pain of using three additional combo classes to the original class - it’s a real disaster if you want to change something in, let’s say, the second combo class…