Responses disappearing while writing


I've been in a frustrating situation a couple times in the last couple days.  Once, I was responding to a response on a thread.  During the middle of my composition, the author of the what I was responding to either deleted or edited his post.  My response (in mid composition) dissappeared without a warning.  Just now, I was in the middle of a response and I saw a strange red error box come up in the top right corner of my screen.  It did go away (I may have clicked it).  Several minutes later, I completed my response and hit OK (or post, or what ever that button says).  My response completely disappeared.  Is there any way of keeping my responses from vanishing?  Even if it can't be posted as is, I would like to be able to copy it and then paste it where it should go.