I got many bad votes and many feedbacks, because the combo was not visible after paying for the addon.

I know, it is not really intuitive and reading the text from combo addon is not natural, maybe because it is too long. I will write it here:

On the bottom of your app, you have 5 shifts. If you press on that and slide your finger to the right or left, you will note that there are other 5 shifts (yes, it is a panorama control).
Slide again and you will see the last 2 shifts. One is a jolly and the other is a "?"-icon, with this icon you can flag your shifts as unsure-shifts.

Once you paid the addon, you will see another button: COMBO-button. This is only visible if you installed the addon. Remember that after installing it, you need to restart the application.

If you have a better idea for the combo, I can update it in the next release. What I don`t want is to put it in the menu, because you use the combo only 2-3 times each year.