[Logician]

if you check javascripts doing this in the web and then apply them to your relevant template (forumhome I guess?) you can create the effect without a hack

But this will increase the length of your source code (thus loading time and bandwidth it spends) so concidering the fact that you already have a "heavy" main page with 40 boards, maybe you should think twice about applying more javascripts on it. My 2 cents..