In qmidiarp's GUI, I'm unable to edit the pattern with the keyboard. That is, I cannot manually enter >000(23)/\1. I can only copy this text from a file and then right-click+paste with the mouse. In QTractor it works fine.
A difference with QTractor is that when opening the GUI in MusE, I get a choice of two GUI types, and selecting the top one does nothing at all. I have to choose the bottom one. In QTractor I get no such choice at all.