Regarding the group filter:
Yes, I can add a player to a group and that group name shows up in the filter. But actually selecting the group in the filter does nothing.
Unless I also enter something in the search field. Then I only see characters with the specified string that are in the selected group.
What I would expect is to see all characters from the group selected in the filter, even without using the search text field.
Another thing I noticed: In my compendium certain special characters are encoded in the following way "&# 8226;" (without the space, since itch apparently auto converts to the proper character). Would it be possible to show this as • ?
One more question: If you add map sharing, will this rely on a (your?) web server or are you going for a peer to peer structure?