Perhaps you've managed to map a MIDI control to the button that shows/hides the Control Window. Can you please: 1) Make sure that MixEmergency is not running. 2) In the macOS Finder, navigate to your Movies folder, then within this to your MixEmergency folder, and within this to the Control Mappings folder. 3) Rename the file "_AUTOSAVE.xml" to "_AUTOSAVE_backup.xml". 4) Launch MixEmergency. Has that helped the issue?