hello, could you provide your latest few submitted crash reports? please enter about:crashes into the location bar, copy the latest few report ids from there starting with bp- & paste them here into a forum reply. this will give us a better understanding what may be triggering those crashes.

bp-7fa54a56-90e7-409e-88d9-958d72150401 01/04/2015 19:08

maybe that's an issue with hardware acceleration - please try to disable hardware acceleration in the firefox menu ≡ > options > advanced > general and see if this makes a difference (that setting will take a restart of the browser to take effect).

It worked :) thanks :) umm, my keyboard messed up. when there is no capslock the lettersare big and when there is they are small.

Is this just with Firefox? What about other programs?

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac Options) key, and then starting Firefox. Is the problem still there?

Wazzapp said

Why does it happen? How can I fix it?

I don't use over browsers. Your solution helped. Thanks.