Does anyone know how to set the ‘Editor’ tab in the Lower Zone to open at the Drum Editor every time? (or to set a new default?)
Preferences/Editors. You there both have the option of “Use Drum Editor when Drum Map is assigned” and setting the Drum editor as the default MIDI Editor (as well as determining whether double clicking and the Open Editors Command opens the lower zone or a separate window).
Sadly you can’t have the lower zone always opening the Drum Editor and the Open Editor Command opening as the Key Editor by default, it’s one or the other for both.