Group Selection on GM Menu
That is true, though. If you're working on a smaller screen, and have to scroll over or down, it's /incredibly/ easy to lose where you are in the rows of checkboxes.
Perhaps a compromise, where we could have a single row of checkboxes that indicate which groups are being selected for /use/, but then continue to fill them in as they're currently working for individual characters? That way, you'd never forget that a group was being used and accidentally reassign it, and you'd know at a glance which groups were open and available - while still maintaining the ease of functionality that comes from not having to hunt down the right checkbox for each individual character (which runs the risk of putting characters into the wrong groups if you get off).