Hi Walter,
Sorry for not replying earlier...
>What happens if in the valid event you do a replace of a different column into the same alias?
Nothing unexpected. The value in the other column is changed.
>If that does not generate the error, I'll see whether I can create a repro..
It's probably something more complex like having expressions as the controlsource or in the Dynamic properties. If I would have to come up with a possible scenario I would think of a valid routine that refreshes the grid which needs to evaluate expressions for the same table in different records. Maybe some of this code closes and opens tables or moves the record pointer.
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Christof