[color:#FF0000][b]Which post is th[/color]at?[/b]
Per those tags, it looks like the "at" in "that" should be bold, but not red, rather than red, but not bold.
If [b] precedes [color:] it comes out as expected.
Is this a UBB.threads bug?
Aaargh!
type a line
highlight it, and select red
[color:#FF0000]this is a test[/color]
now highlight from "this"
to the end of the line (which therefore includes the /color tag) and select BOLD
[color:#FF0000][b]this is a test[/color][/b]
and that's how you cross-nest tags. spin the wheel of fortune to guess how it's going to mark it up.
(also just now I tried to bold "that's" and failed, because the parser still has a bold stuck in its craw)