Run Code To Fill Cells On Drop-down Change

I am busy with a project using VBA to populate a spreadsheet based upon the data entered into a particular cell. The problem that I am experiencing is that I populate the initial cell via a combo-box which I cannot exit unless I click elsewhere with my mouse. The code that I am using to populate the other cells is as follows

Private Sub Worksheet_Change(ByVal target As Range)
Application. ScreenUpdating = False
On Error Goto dump
Dim r As Range, MyRowNum As Long, ws1 As Worksheet, ws2 As Worksheet, strPriCode As Variant, _
strNAPPIE As Long, strSInCost As Currency, strSInDesc As String
Set ws1 = Worksheets("SINVOICE")
Set ws2 = Worksheets("STOCKIMP")
Set r = ws1.Range("B11:B35")
If Intersect(target, r) Is Nothing Then Exit Sub
If target > 0 Then....................