Hi Patrice Boissonneault,
As previously stated the Custom Behaviour as well as Calculated properties are currently not supported at all. If you were to specify them through the designer you will get the default behaviour for the selected property. The default is Persistent.
If you however have a column that is calculated on the server you can use PersistentReadOnly to make sure it is accessed correctly and not inserted.
I am sorry for any inconvenience that this has caused you.
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