I record this short video to demonstrate the problem - Firefox Copy and Paste bug/problem on Facebook site (issues with copy paste in Firefox) https://youtu.be/ST-kHHBh6f0 In video you can see Firefox (with cleaned cache/all history+cookie and restarted to SAFE MODE) in compare with Chrome with copy/paste any some text. In Firefox strange bug, that after paste text - and press enter - it's shows only one row (!), or only one sentence, randomly jumping when you try editing!!! It does not matter if I use context menus or Keyboard commands to copy & paste (CTRL C & V)! Pasting causes two graphical appearances of the pasted text. Safe modes of any (windows & firefox), issue still repeatable. No other browser has this issue. And in the same time in video you can see that In Chrome all selected texts - copied and pasted fine all time. This bug going me crazy, very annoying. I never had this bug, only last time its always frustrates me (about 2+ month!) I use Firefox for a very long time and never see this kind of bug before! Firefox about http://i.imgur.com/v81jLxe.png My PC Win7 64x about http://i.imgur.com/EjiYtXm.png I read this topic https://support.mozilla.org/en-US/questions/1083345 but no solution or fix found. I really do not understand what Firefox developers think about, why can't fix this issue? Why in Chrome all okey, but in Firefox this bug still not fixed?