How to make button appear pressed with right click

public partial class Form1 : Form
{
   ToolStripMenuItem activate = new ToolStripMenuItem("Activate");
   ToolStripMenuItem deactivate = new ToolStripMenuItem("Deactivate");

   public Form1()
   {
      InitializeComponent();

      ContextMenuStrip cms = new ContextMenuStrip();
      cms.Items.Add(activate);
      activate.Click += new EventHandler(ActivateClick);
      cms.Items.Add(deactivate);
      deactivate.Click += new EventHandler(DectivateClick);
      button1.ContextMenuStrip = cms;
      activate.Enabled = false;

      // if the button is disabled the mouse event is sent to its container control
      button1.Parent.MouseUp += new MouseEventHandler(Parent_MouseUp);
   }

   void Parent_MouseUp(object sender, MouseEventArgs e)
   {
      Control ctl = this.GetChildAtPoint(e.Location);
      if (ctl != null && !ctl.Enabled && ctl.ContextMenuStrip != null)
         ctl.ContextMenuStrip.Show(this, e.Location);
   }

   private void ActivateClick(object sender, EventArgs e)
   {
      button1.Enabled = true;
      deactivate.Enabled = true;
      activate.Enabled = false;
   }

   private void DectivateClick(object sender, EventArgs e)
   {
      button1.Enabled = false;
      deactivate.Enabled = false;
      activate.Enabled = true;
   }
}