My playback area (yellow bar at top) shrinks to nothing (cannot modify), which makes it nearly impossible to do any work in my session. I'm using the latest version of Magix Music Maker on a Dell Inspiron 15 3000 laptop.
In addition to what @SP. has suggested, have you also tried carefully grabbing the right hand edge of that yellow bar and dragging it to the right, thus extending it?
It is annoying to have to do this but it does work, at least on my system.