[pmwiki-users] Link text in (parentheses) will not be not displayed?

[Derek Lerner]

Somehow in the process of tweaking a new skin design the wiki I'm  
working on lost the ability to hide category links.

Instead of [[!(Projects)]] being hidden, a link pointing to  
Category.Projects is displayed as "Category" on the page. Hiding  
standard wikilinks [[(Projects.TheProjectsTitle)]] is still  
functioning though.

Where is this function being defined?
What code should I look for in order to try and isolate this issue?

Any help or suggestions would be greatly appreciated.

Kind regards,
Derek