ScrewTurn Wiki is an excellent free wiki engine that I love and that I’ve written a source code syntax highlighter plugin for.
The plugin literally just hooks in the client-side SyntaxHighlighter by Alex Gorbatchev. Alex has published a new version some months ago. The version 3 has better support for copy&paste without the need for buttons in the toolbar, and some added elegance in its internal structure and extensibility. The new version of the plugin simply uses this version; there’s not much else to be said about it.
If you’re using the ScrewTurn wiki plugin with your own downloaded version of the SyntaxHighlighter, it’d be best to update to version 3 as well. You can use ScrewTurn’s auto-update functionality to obtain the new version of the plugin.