private void tabControl1_SelectedIndexChanged(object sender, EventArgs e)
 {
     if (tabControl1.SelectedTab.Name == "tabPagePreview" &&
         dataGridView1.CurrentRow != null
         )
     {
         FileObject a = (FileObject)dataGridView1.CurrentRow.DataBoundItem;
         richTextBox1.Text = a.GetFileAsString(cde.BasePath);
         HighlightRTF(richTextBox1);
         groupBoxSearchInPreview.Enabled = true;
     }
     else
     {
         groupBoxSearchInPreview.Enabled = false;
     }
 }