Already did that. With the old driver (v10.something) the scroll did not worked at all in FF4. After installing the latest synaptics driver (v15.2.7) it started to work only for one minute after FF4 is started.

After updating the driver I thought "oh, look, It worked! (happy)" then after about one minute... disappointed. :(

I have nothing else to do just to wait for a FF4 update and hopefully this bug will be solved.

Edit: Luckily most of the time I have a USB mouse handy in order to use while browsing, so it is not such a big thing. Though it is a little bit annoying when I need to use the touchpad.

Bleah! New day new problem.
I'm seriously thinking to go back to FF3.6 :(

Today FF4 started to stutter and eventually hanged.
I had to end task and restart FF4.

This never happened before in FF3.x.

You can try and uninstall Firefox and then start a new profile for it; it really sounds like you're having issues with a corrupt profile or some problems with other software running.

Quick question, are you running the Acer software that came with your laptop (please please tell me no)?

No :) I hate it.

I will try reinstalling FF4.
This is a rather clean install. I reinstalled the OS one month ago and I don't use to install all king of crappy software that I don't need. I like my windows clean and functional.
Also I don't have any fancy plugins installed in FF.

When the stutter began I was browsing youtube so this may have had an effect.

Just want to post an update about my issue with touch-pad scrolling.

I found the culprit which is Adobe Acrobat 10.0.1.434 Add-on!

Once I disabled acrobat add-on, scrolling resumed right away (without FF4 restart)!