cursor changing position when typing in firefox

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http://forums.fedoraforum.org – I'm on FC17 - a recently upgrade system. I'm having issues when typing in Firefox - as I'm typing, the cursor will just randomly jump to some other random place in the text. As I'm mostly typing in Firefox, I don't know if the problem is in Firefox or in another package. Anyone have any ideas? Thanks for any help. (HowTos)