Solo buttons not working in v4.x

I can’t get the solo buttons to work. I can mute all the tracks I don’t want to hear and effectively solo the track I do want to hear - but that’s the long way!!!

I have a P4 2.53Ghz, 512mb RAM, M-Audio Delta 1010LT, WinXP SP2.

I’ve tried all of the V4.x versions that are still downloadable. Is anyone else having this problem?

Using build 2099 and no problems with soloing of tracks. Tried turning on in both track view and the track mixer and worked fine.