>>3311373grease monkey, a browser extension that lets you run custom javascript (also known as user scripts), have their own commands, that are supported by all other similar extensions.
extraflags, and /bant/ flags, rely on some of these commands to make the box where you select your flag appear.
grease monkey recently did a massive overhaul of their code, and in the process removed the commands that extraflags and /bant/ flags need to function, and show no signs or reimplementing them.
>>3311404GM_addStyle is only necessary to style the box created by GM_addMenuCommand. it's irrelevant if you can find away around using GM_addMenuCommand