PlayN and Firefox issues

I am working on a pet project of a Facebook game.

I've had a couple of problems until now on Firefox browser.

• CPU runs wild when you start a game on FF.
• TextLayout gets moved a few pixels up.
• Caching ruins reloading of resources

Anyone had these kind of problems?

Ok, here is why TextLayout is moved up: FF bugzilla

Also after a lot of googling it seems that drawing on canvas has performance issues in FF.