To All,
I think the x,y,x problem is probably related to me doing a requery in the valid when a new value has been entered via the combo box. Removing this cured the problem.
The problem also could have been related to me playing fast and loose with the selstart and sellength props.
Thanks for the help.
"The Iron Fish: The water is cold...but the fish don't mind"
...Jay Jenks, boyhood chum
