title: disabling button after clicking it
body: <p>i have here 3 buttons.</p>
  
  <p>when i click on the button 1, it will disable button 1 then  enable the second button,  then same proces as it reach the last button. but i think there is something wrong with my code. it doesn't disable when i click on the first button  </p>
  
  <p>button1 is enabled and button2 and 3 is disabled when it loads.</p>
  
  <pre><code>private void groupBox1_Enter(object sender, EventArgs e)
  {
      Button btn = sender as Button;
  
      if (btn == button1)
      {
          button1.Enabled = false;
          button2.Enabled = true;
          button3.Visible = false;
          button3.Enabled = false;
          MessageBox.Show("button 1 disabled");
      }
      else if (btn == button2)
      {
          button1.Enabled = false;
          button2.Enabled = false;
          button3.Visible = true;
          button3.Visible = true;
          MessageBox.Show("button 2 disabled");
      }
      else if (btn == button3)
      {
          button1.Enabled = false;
          button2.Enabled = false;
          button3.Visible = false;
          button3.Visible = false;
          MessageBox.Show("button 3 disabled");
      }
  }
  </code></pre>