Ubuntu – Tail keeps snapping to the bottom after i scroll up with mousewheel

I'm having a problem with tail in Xubuntu (Xfce 4). In my previous ubuntu install (Ubuntu 9.10), if i was tailing a file with tail -f myfile, i could scroll up with the mousewheel to look at an earlier part of the file.

Now though, if it's a file which is being updated while i look at it (like a log file) whenever any new text is updated to the end of the file, the view snaps down to the bottom again, away from the part i was looking at.

This is really annoying, does anyone know how i can change the behaviour?

thanks, max