Gunnar,
I didn't expect it to change the data session. It's already in that session. Only wanted to note &CommandDS was wrong. You could test this way:

if Type("_screen.ActiveForm") = "O" and !isnull(_screen.ActiveForm)
 if _screen.ActiveForm.Datasession = 2 && Private
    set datasession to _screen.DataSessionID
    _screen.Print('Screen'+trans(set("DataSession"))+chr(13))
    set DataSession to _screen.ActiveForm.DatasessionId
    _screen.Print('ActiveForm'+trans(set("DataSession"))+chr(13))
    set DataSession to
    _screen.Print('Current'+trans(set("DataSession"))+chr(13))
 endif
endif

Cetin

>Hello Cetin
>
>hmm, didn't know that about the error on ds. but sorry, still doesn't work. i tryied your 2 suggestions and even hardcoded for testing purpose the ds id - no effect, the command does not switch the ds.
>
>
>>
>>Gunnar,
>>Sorry couldn't read the whole thread and don't know if you already checked this. The macro substition there looks like as the culprit. Set datasession doesn't error with macro substition even if it was something erroneous ie: DummyVariable is not defined and:
>>set datasession to &DummyVariable
>>doesn't error and doesn't do anything (as if you did "set datasession to")
>>
>>

if Type("_screen.ActiveForm") = "O"
>>	CurrentDS	= set("datasession")
>>	CallingFormDS	= _screen.ActiveForm.DatasessionId
>>	if CallingFormDS <> CurrentDS
>>		ResetDS = .t.
>>		set datasession to CallingFormDS
>>* or
>>		set datasession to _screen.ActiveForm.DatasessionId
>>	endif
>>endif

>>Cetin