well thanks both of you!

i actually did do it your way Cetin! ( sort of )

the controlsource was set to the memory variable for the field in question
but this then lost whatever the combobox selection was.

so i then set it to the actaul field data - but then i lost the cancel function for that field.

so.....

on clicking the edit button i stored the initail value for the field, then if cancel was selected i replaced the (possibly changed) value of the reference field back to the saved value.

probably the wrong way to do things but it works