Wikimedia Bugzilla is closed!

If a command is the parameter of another command, the bracket matcher does seem to get confused.

Example:

\setlength{\tabcolsep}{5pt}

Here, the two bracket pairs are colored as:
\setlength[1{]\tabcolsep[}2][{2]5pt[}1]

The correct bracket pairs are:
\setlength[1{]\tabcolsep[}1][2{]5pt[}2]

For a live example, see: http://en.wikibooks.org/wiki/LaTeX/Tables#Space_between_columns

Hint: the code there is generated by the "LaTeX/LaTeX" template which uses the <source> tag, if this is of any importance.