The title says it all. Using the trackpad (Macbook owner), I can't highlight any text at all, not even the text in the address bar.

This applies to all websites, but not to any other programs i.e. this problem only occurs in safari. I am running OS X 10.4.9 and have done all the updates. Since I have started using safari, I haven't installed any plugins that I know of.

I can't remember how long it has been like this but I do remember a time when it wasn't.

Any clue on what it could be?