title: Unable to change label text on the popup
body: <p>I dont understand why it doesnt work.
  I want to set label's text outside from popup form.</p>
  
  <pre><code>class BaseForm : Form
  {}
  
  public class BasePopup
  {
      private Form popupForm;
       private Panel controlPanel;
      private Label controlLabel; 
  
      public BasePopup()
      {
          popupForm = new BaseForm
          {
             ...
          };
  
          controlPanel = new Panel { Dock = DockStyle.Fill, BorderStyle = BorderStyle.Fixed3D };
          popupForm.Controls.Add(controlPanel);
  
          controlLabel = new Label { Location = new Point(30, 30), Text = "AAA" };
          controlPanel.Controls.Add(controlLabel);
      }
   }
  
   public string ControlLabelText
      {
          get { return controlLabel.Text; }
          set { controlLabel.Text = value; }
      }
  
  public class ComboBoxPopup : BasePopup
  {
  }
  </code></pre>
  
  <p>Usage:</p>
  
  <pre><code> var txp = new ComboBoxPopup();
          txp.ControlLabelText = "Please select the language";
          new ComboBoxPopup().ShowDialog(this);
  </code></pre>
  
  <p>Text saves here - <code>controlLabel.Text = value;</code>
   but label's text doesnt change. I tried <code>Application.DoEvents()</code> but no luck.</p>