Reuse of DGV doesn't fill the grid

[RafStorr]

I have an invoice form using a data grid (DGVInvoice). When I start to enter a description, this shows another grid in the same Form (DGVMatches) that shows all matches from the Invoice/Description field in the database. Clicking any of the matches updates the DGVInvoice description field.

This works perfectly on Line 1 of the invoice, but when I enter a description on subsequent lines, no matches are displayed in DGVMatches (although the DGVMatches header shows the search term correctly).

Code in DGVInvoice to call DGVMatches:

Private Sub ShowMatches()

      ' @@ Fetch Descriptions from LineEntry table
      Dim pSQL As String = "SELECT DISTINCT [Desc] FROM LineEntry WHERE [Desc] LIKE '" & mCellContent & "%' ORDER BY [Desc] "
      Dim m_Datatable As New DataTable

      Using cnn As New OleDbConnection(gs_Connection)
          cnn.Open()
          Using dad As New OleDbDataAdapter(pSQL, cnn)
              dad.Fill(m_Datatable)
              dad.Dispose()
          End Using
          cnn.Close()
      End Using

      GbMatching.Text = "Matching entries for '" & mCellContent & "'"

      If m_Datatable.Rows.Count = 0 Then  ' ** No data
          GbMatching.Visible = False
      Else
          With DgvMatches
              .DataSource = m_Datatable
              GbMatching.Visible = True
              .Columns(0).Width = 360
              .Columns(0).DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleLeft   ' @@ Aligns cells
              .Refresh()
          End With
          m_Datatable = Nothing
      End If

    End Sub

Code in DGVMatches to fill the DGVInvoice Description field:

Private Sub DgvMatches_Click(sender As Object, e As EventArgs) Handles DgvMatches.Click
      With DgvInvoice
          .CurrentCell.Value = DgvMatches.CurrentCell.Value         
          DgvInvoice.BeginEdit(False)
      End With

      GbMatching.Visible = False
      mMatchFound = True
      DgvMatches.Dispose()

  End Sub

Can anyone help with this?