I just upgraded to mep 2011. this problem has persisted through 2010. frequently when I use the undo command
the background will change to grey. almost like when you use a 3d rotate command, or edit a block. its not the same grey
though, I went into options and adjusted the color to see if it was sending it to one of those modes. when it turns this grey,
everything runs slower. the only way I can get the background back to black, and running smoothly is to change the viewport
configuration. for example if I am using �3 right� I have to change it to another configuration. any ideas?  
thanks for your help

i know this is pretty vague and weak, but thats all that i can come up with. i dont know what its doing, or even how to trigger it. it just happens most of the time after a few undos, a redo does not remedy it either. it will redo the drafting, but not the grey screen and slow.

Sorry if nobody has answered your question yet. It's not that your description is lacking anything - in fact, it does look pretty detailed, thank you.Our response time is usually based on a couple things:1) The complexity of your issue - which yours seems to be pretty complex. And/or,2) Our current workload. I can't speak for anyone else, but today has been another swamped day for me. I can almost assure you that someone is/has been looking into your issue and hopefully you'll have a fix/suggestion soon.

thats great, im not trying to come across impaitent. just trying to add as much description as i can. thanks

Are you running any custom lisp routines?