Yeah, I fixed up that feature while I was working on the code.
I know the icons suck, but I didn't want to use the default MyBB (1.2.9) images because they have some dodgy inconsistencies... :\
<-- "unread" vs. "unread dot"
<-- "unread dot" vs. "read dot" (quite hard to tell the difference =p)
So I just put some simple black triangles on the existing icons.
If someone comes up with a better idea I'll use it.