private void newToolStripMenuItem_Click(object sender, EventArgs e)
 {
     InnerForm newMDIChild = new InnerForm(counter);
     newMDIChild.MdiParent = this;
     newMDIChild.Show();
     counter++;
     menuStrip1.MdiWindowListItem = windowsToolStripMenuItem;
 }
 private void openToolStripMenuItem_Click(object sender, EventArgs e)
 {
     if (openFileDialog1.ShowDialog() == DialogResult.OK)
     {
         InnerForm newMDIChild = new InnerForm(openFileDialog1.FileName);
         newMDIChild.MdiParent = this;
         newMDIChild.Show();
     }
 }