I clicked send, it sent, then it crashed. I also had several tabs open, most of which were pretty harmless. One was pandora.com Can't reproduce the bug, only happened once.
Do you have a crash log for this crash?
Created attachment 19164 [details] crash log
This bug is the same as bug 17057, and the JS part of the stack trace is the same as second stack trace posted in that bug.
Closing as a duplicate per the above comment - I don't think it helps to track unreproducible crashes with the same stack trace separately. *** This bug has been marked as a duplicate of 17057 ***