When I launch an offline game of Titan (module 1.2) and I select one color to play, I cannot switch sides to play another color. The legion markers are only available for the first color I choose.
Windows 64-bit PC, 16 GB RAM, Vassal Version 3.7
I took a quick gander at this module and cannot really make sense of how it’s organized without dipping into the Editor. The only thing I can do is confirm your experience–once you switch colors, it doesn’t seem possible to bring back the window of legion markers for the new color. They are all private windows configured to neither have a toolbar button nor a hotkey to open the window via the keyboard.