In former Firefox (FF) versions themes and Personas worked together even if you had to install an old Personas version. Even FF 5 let it be if theme and Persona had been chosen already. Only FF 6 says that you MUST use default theme with Personas (or the lightweight build in) OR use themes without Personas. If you use a theme and mouse over a Persona it shows happily in the background TOGETHER with the persona but when you want to use it the theme switches back to "default" which is a very big theme. If you look up in the extension help it only says that with Personas only work with default theme. And if you ask "why?" they say it was designed that way. WOW great! It did work together already but someone put in a switch saying: you are not allowed to use them together! I recently updated my small Computer from FF5 (with Persona and theme working together) to FF6.0.1 and it continued to work together! So I upgraded my main PC to FF6.0.1 and the problem persisted. THIS IS RIDICULOUS!!! I vote that FF should be customizable and user friendly!