Firefox 3 is really fast with tersus!!!
There are no important compability issues, but there are some minor issues.
I'm using Firefox 3 from beta 5 (about 2+ months) with tersus and the only problems I saw, are:
1. Bigger font on www.tersus.com in menubar (Home, About The Platform, Download........) - and only here font is bigger
2. Text field is shown out of the dialog (example below). This happens only in one dialog in our application and only in firefox 3. I have not tried to play with it so can not say anything about propably cause.
For best results, use the Firefox browser..