Tip for days like today when we have 'disappearing posts' - copy before posting so if it disappears (especially if it's one of those agonising long ones! ) you can paste it in the box on the next try. Not sure if it stays there but each time I tried I copied it again just to make sure!
How to copy and paste:
Highlight the text.
Cursor over text, right click, copy.
Go to new message box.
Cursor in box, right click, paste.