Description of the issue: How can this issue be reproduced?
Sometimes typing in a Facebook tab will result in an inability to post the status message or chat message with Enter. Enter will just produce a new line. (Caps Lock is not activated and Shift is not being held down)
Expected result:
When Enter is pressed, the post or message should be sent or posted.
Try going back to your main profile and disabling all of your extensions? If that solves the problem, the next steps would be to enable each extension one by one, and seeing which one causes the issue.