Hello, Ken.

Are you "filtering" the records/recordsets you show in the grid? If so, how? Are you using the table as the recordsource or a parameterized view?

>Is any one know how to fix it?
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>It happen only when 3 or more user working on the same form and one user updating a table. Very often the other users' screens automatically update after the first user saves data. I make sure the key field use unique value with sys(2015) function on master table and copy the unique value to child table. But it didn't work.
>
>It not just happen on one form but many form using the same type of buffering as following.
>
>Master table Optimistic row buffering
>Child table use Optimistic table buffering