Maybe not the ideal solution for you, but: In the upper right corner of either map (minimized or maximized) there are two small boxes. The first is for "Auto Scale" and the one farthest right is for "Close / Unlock" if you have the map locked, or "Close / Menu" if you
do not have the map locked. Right click this box, and if the map is locked, it will unlock it so you can r-click it again to get the menu. The first option is to "Hide in Combat", the second is to lock the map. I can tell you that it does work and the map definitely hides at the first hint of combat. That option has saved my wrinkly old butt more than once.
The instant you leave combat the map automatically re-appears.