I found the ‘problems’ very early on, but perhaps it was that I had not learnt to be able to accurately select small areas, because I just tried again without any problems.
So I retract that there are problems with the buttons per se, but some are rather small for making adjustments easily.
However, the other program I have mentioned, MYOB, is non-responsive to touch in its own dialogs, and it does have very big buttons.