I haven't seen this before, I use this button often, but today, when I commented on this post:
I selected a piece of my text in the edit window, then clicked the >> button on the toolbox.
The menu expanded, and shows two syntax highlighting options.
The first one only has a subset of 4 highlighting options.
Then, a few menu options lower, there is a second option with the same name (also some other entries in the menu are double).
That one has the full set of highlighting options.
update: seems to only happen on the roadtest page. When I comment on blog posts, the menu is normal.
Now that's odd.
It's clearly a bug - the roadtest page is entirely custom and mostly my code, so I've done something stupid somewhere.
I'll get a ticket logged for it. Thanks for pointing this out jancumps
I noticed you didn't have the exterminator badge - so now you do