When you change the mouse mode to... lets say the arrow it wont let you?
I am not sure, I don't use MIDI, but I have Music Maker 16 and I just opened the program and right clicked on track one to open a new MIDI object, there was data already entered there, I then selected the magnify glass and licked around... zooming into the project.
I then selected a different MIDI object tool (Velocity) and changed the velocity. I cannot get it to stick to the magnify glass
I am not sure you are doing anything wrong. I am trying to duplicate your situation, but anything I do, I am able to select a different mouse mode, even using the CTRL + (1-7) give me a different mouse mode.
I suggest backing up any files you have created and reinstalling the software, see if that helps.
The same thing is happening to me. MM17, right? Normal click is stuck on Magnify, but holding down CTRL returns to the selected tool for as long as you hold CTRL down, which ends up copying notes when using the Move tool. I've gotten it to go away before, but I can't remember how at the moment.