form with tab control takes a long time to open

You could keep the subforms as 'regular forms' and add buttons to open the forms as needed.  (Why keep subforms on a 'parent' form if you aren't going to load them?)

Scott C

whao mbizup you're a genius!! didn't think of that haha! (psst i didn't even know there was such a thing as source object!! haha, man i really need to up my skills!!)

thanks for your post scott, it's more for a UI thing that the user sees it as a tab rather than individual forms - so more of a UI design choice = )

fyed, yup yup, i had my event in the existing database as a on tab change event = ) thanks for your advice!

mbizup i got inspiration from your decoupling of the objects to also decouple the recordsource setting the subform's recordsource to nothing by default. thanks!! = ))

    Case "MTK Summary"
        Forms!frmMTKManager!subfrmMTKSummaryDatasheet.SourceObject = "subfrmMTKSummaryDatasheet"
        If Me.txtManagersTeamCode = 2 Then
            Forms!frmMTKManager!subfrmMTKSummaryDatasheet.Form.RecordSource = "qryMTKSummary"
        ElseIf Me.txtManagersTeamCode = 3 Then
            Forms!frmMTKManager!subfrmMTKSummaryDatasheet.Form.RecordSource = "qryMTKSummaryServicing"
        End If

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You don't need to decouple the Recordsource from the subform.

Assuming that your subforms are supposed to be linked to your main form, you may also have to set the values of the LinkMaster and LinkChild properties of the subform control.  I ususally use something like:

    Select Case Me.tab_ControlName.Pages(Me.tab_ControlName).Caption

        Case "Details"

            if me.sub_Details.SourceObject = "" then
                me.sub_Details.SourceObject = "frm_Details_Subform"
                me.sub_Details.LinkMasterFields = "[TransID]"
                me.sub_Details.LinkChildFields = "[TransID]"
            end if

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The advantage of this method is that it will only reset the SourceObject if it has not already been established, and it ensures that the main form and subform are linked properly.

great thanks fyed, could you respond to this new question i created? thanks!

"optimising subforms in tabbed controls"

You are correct that if your subform is not actually linked, then you can leave out the portion where you set the LinkMasterField and LinkChildField properties.  That just ensures that if they are supposed to be linked, they link properly.

The thing that takes the time when loading multiple subforms is running the query to populate your subform.  If the subform is based on a simple table, the subform will populate almost instantaneously.  But if you have a query, then it takes a bit longer.  If you have multiple subforms, on multiple tabs, each one has to process (sequentially).  That is why I generally leave the SourceObject blank until the tab that it is on is first accessed.

Sometimes (if there are a lot of subforms or some of them take a while to populate) I'll even set the SourceObject of some of the subforms back to "" as I navigate between records on the main form.  Just depends on how many and how complex the queries are.

whao cool! ok great, learnt something new here = ) i didn't think of setting the subforms' sourceobject back to "" to save the querying time.

thanks fyed!!

Always glad to help.