title: Problem with adding item to the list from another form
body: <p>I would like to click &quot;add button&quot; to add contacts to the list of contacts in ClientApp, but nothing added to box, only to a list named users.</p>
  <p>I want to see new usser nickname on the listbox. But when I evokes function AddContact from other form I don't see new usser on the listbox, from this same is good.</p>
  <p>In atributes I see this cell, named &quot;dwa&quot;.</p>
  <p>Someone will help?</p>
  <p>AddUsser:</p>
  <pre><code>  public partial class NewUser: Form
    {
      ...
  
       public void New()
       {
          ClientApp.users.Add(new accounts(textBox1.Text, textBox2.Text));
          ClientApp x = new KlientApp();
          x.AddContact(textBox2.Text);
          this.Hide();
      }
    }
  </code></pre>
  <p>ClientApp:</p>
  <pre><code>public partial class ClientApp: Form
  {
      ...
  
      public void AddContact(string nick)
      {
          contacts.BeginUpdate();
          contacts.Items.Add(nick);
          contacts.EndUpdate();
      }
  }
  </code></pre>
  <p><a href="https://i.stack.imgur.com/LK5aI.png" rel="nofollow noreferrer">enter image description here</a></p>
  <p>To Gellio Gao.
  I sew ObjectDisposedException in private void Msg when I close program on go:</p>
  <pre><code> private void ShowMsg()
  {
      bool temp = true;
      while( temp == true)
      {
          if(DateTime.Now.Second % 3  == 0)
          {  
              Msg();
              showed.WaitOne();
              showed.Reset();
              showed.WaitOne(1000);                  
          }
      }
  }
  
    private void Msg()
  {
      ClientLog.send_msg= &quot;Wyswietl wiadomosci&quot;;
      ClientLog.received.Reset();
  
      Thread wątek = new Thread(new ThreadStart(AsynchronousClient.StartClient));
      wątek.IsBackground = true;
      wątek.Start();
  
      ClientLog.received.WaitOne();
     
      Invoke(new Action(() =&gt;
      {
          if (ClientLog.send_msg!= &quot;&quot;)
          {
          messages.AppendText(ClientLog.send_msg+ Environment.NewLine);
          }
      }));
      showed.Set();
  }
  </code></pre>