Maybe it may sound weird, but for some cases it is not just enough to have different solid colors of your nodes background. I would like to have option that allow you to configure unique background pattern of the created group -
color noise (ability to configure gradient of background, it’s noise - like voronoi etc, ability to use multiple colors for your background - it will allow you to make rainbow background for landscape that work with “RainbowLands location” or make a white-black lined background for group of nodes that creates “GrayLocation”)
texture configuration (ability to add image into your background, or add text to background like “HERE IS FIRE-LOARD GROUP OF NODES” “HERE IS SPIDER-LOCATION GROUP OF NODES” that will be infinitely copied through all background space of group - ability to configure scale of texture and/or text, etc. Also option to mage background image auto-scaleble, so if you will change proportion of your group - your image will follow changing of group size) and etc. Image how cool it will be to load image with castle, mountain, forest, with snowy taiga wolves on the background of nodes that processed “Snowy Location” of your map
all of those improvements will make experience from projects navigation better. Espasialy for WorldMachine geeks like me 
maybe users can suggest other ideas about customization of Group things
