Private Sub ProjectPanelDataDataGridView_MouseDown(ByVal sender As Object, _
      ByVal e As System.Windows.Forms.MouseEventArgs) Handles _
      ProjectPanelDataDataGridView.MouseDown
        If e.Button = Windows.Forms.MouseButtons.Right Then
            'If Me.ProjectPanelDataDataGridView.CurrentCell.ColumnIndex = "28" 
            ' Then
            'If Me.ProjectPanelDataDataGridView.he.CurrentCell.ColumnIndex = 
            ' "28" Then
            '    Form_ProjectHistory.Show()
            'End If
 
            For i As Integer = 0 To ProjectPanelDataDataGridView.Columns.Count _
              - 1
                If ProjectPanelDataDataGridView.Columns(i).HeaderText = _
                Me.ProjectPanelDataDataGridView.Rows( _
                Me.ProjectPanelDataDataGridView.CurrentRow.Index).Cells( _
                GetColumnNo("Proj. history")).Value.ToString Then
                    Form_ProjectHistory.Show()
                End If
            Next i
 
        End If
    End Sub

    Public Function GetColumnNo(ByVal HeaderName As String) As Integer
        GetColumnNo = 0
        If HeaderName <> "" Then
            For i As Integer = 0 To ProjectPanelDataDataGridView.Columns.Count _
              - 1
                If ProjectPanelDataDataGridView.Columns(i).HeaderText = _
                HeaderName Then
                    GetColumnNo = i
                    Exit For
                End If
            Next i
        End If
    End Function

Private Sub XDataGridView_CellMouseClick(sender As Object, e As _
  DataGridViewCellMouseEventArgs) Handles XDataGridView.CellMouseClick
 
  If e.Button = System.Windows.Forms.MouseButtons.Right Then
    If XDataGridView.Columns(e.ColumnIndex).HeaderText = "Proj. history" Then
      Form2.Show()
    End If
  End If
 
End Sub