HELP : Purchase Order Entry Tax Recalculation..

[tommytun]

Hi all,,
I am new at GP. I have a problem with costimization in recalculate the Tax value.
The program is Transactions\Purchasing\Purchase Order Entry

I inserted some customized coding of recalculating of Tax in Sale Transaction Entry.
It's ok in Sale Transaction Entry's Tax recalculating.

below is my coding in Tax_Changed event...

Me.strlOLDTAX = Me.Tax.Value
If Me.strlOLDTAX = Me.strNEWTAX Then
==> exit sub
Else
End If
Call SetCalcTax(Trim(Me.TaxScheduleID.Value))
If Me.dbltax <> 0 Then
Me.Tax.Value = strCurrSym + CStr(Me.dbltax)
End If

If the old tax nad change tax value are the same .. no calculation.
The problem is here ==> when I trace in this event, the code is go to exit sub and then after go out of this event .. it load Purchase Order Tax Summary form in behind and show a dialog box to me as ... with the title of "Great Plains" and message text is "You must close the Purchase Order Tax Summary Entry Window before continuing." and with "OK" button.

And I noticed that I didn't do any coding to load the PO Summary Tax form. The Tax is recalculated as I excepted except to this dialog box showing.

Where can I terminate this dialog box? or Need I implement something in my coding?

help me...
Tommy Tun