Global options don't always work correctly
The MCCheckOut page (e.g., here) has some issues with the global options: sometimes the same type of option is parsed differently, sometimes options with names wind up being anonymous, etc.
#1 Updated by Jeremy Wolcott about 4 years ago
The solution, I suppose, is to hash the combination of the label and the contents of the drop-down box -- we don't care what "group number" it was when the plot was being made, just that they're semantically the same now. Then write out global drop-downs for unique hashes, and match them to plots that way.