Still learning StrataFrame...

I can't figure out how to localize the StrataFrame collision form and how I could put it on top

Myform.TopMost = True and Myform.MyBrowseDialog.ForceWindowTopMost = True, so collision form is always on bottom

Is the event being raised and there is nothing in the event args, or is the collision not being detected?  If the collision is not being detected, you can always turn on Debugging for the data source (MicroFour.StrataFrame.Data.DataBasics.DataSources("").SetDebugOn()) and check the command that is being executed to make sure that it would be albe to find the collision.

Thanks Ben,

I begin to understand... here is the SQL command really sent by the BO (concurrency mode set on allfields, so all the additional WHERE clauses are correct):

@volumax_ORG was 10 on A client side when BO was filled, and User B upadated its related field to 100 before A asked for deletion.
So my SQL command would never raise an exception, since there was no line matching on the server!

I totally misunderstood the purpose of DeleteConcurrencyType, wich is only to add the additional where clauses, right?

How could I retrieve the result of the delete command (boolean or #line deleted) without writing a specific procedure?
Or is it a better practice to create a property "is_deletabled" on my BO class, and to check in beforedelete method to switch that property to True or False, so it could be retrieved by beforedelete methode on UI layer?

and the SetDebugOn is really a very nice tool

Hrm.  That is very odd.  The addition of the extra parts to the WHERE clause will prevent the line from being deleted (just like it should), however, it should be raising an concurrency exception.  Looking at the source code, if the local line is deleted, it will raise the ConcurrencyException just like normal. 

Just out of curiosity, are you expecting to wrap the Save() in a Try/Catch or are you handling the ConcurrencyException event of the business object?