Wherever I'm posting, I write it first in a text editor. Especially if it's a long post, because it's worth checking to see if someone else has posted while I was writing. I then copy and paste into the forum. If it fails to take then I just paste again.

It actually happened here today. I think I might have clicked on 'Home' too soon. Anyhow it was still on the clipboard so I pasted it again and it took.