private void btnKosz_Click(object sender, EventArgs e)
 {
     if (listBox1.SelectedItems.Count == 0)
     {
         return;
     }
     try {
         if ((cmbFolders.SelectedItem as Imap4FolderItem).imap4Folder.Name == "Trash")
         {
             foreach (MailItem mailItem in listBox1.SelectedItems)
             {
                 mailClient.Delete(mailItem.mailInfo);
             }
             mailClient.Expunge();//było zaznaczone, teraz usunięte
             List <MailItem> mailItems = new List <MailItem>();
             foreach (MailItem mailItem in listBox1.SelectedItems)
             {
                 mailItems.Add(mailItem);
             }
             listBox1.SelectedItems.Clear();
             foreach (MailItem mailItem in mailItems)
             {
                 listBox1.Items.Remove(mailItem);
             }
         }
         else
         {
             Imap4Folder trash = null;
             foreach (Imap4FolderItem imap4FolderItem in cmbFolders.Items)
             {
                 if (imap4FolderItem.imap4Folder.Name == "Trash")
                 {
                     trash = imap4FolderItem.imap4Folder;
                 }
             }
             foreach (MailItem mailItem in listBox1.SelectedItems)
             {
                 mailClient.Move(mailItem.mailInfo, trash);
             }
             foreach (MailItem mailItem in listBox1.SelectedItems)
             {
                 mailClient.Delete(mailItem.mailInfo);
             }
             mailClient.Expunge();
             List <MailItem> mailItems = new List <MailItem>();
             foreach (MailItem mailItem in listBox1.SelectedItems)
             {
                 mailItems.Add(mailItem);
             }
             listBox1.SelectedItems.Clear();
             foreach (MailItem mailItem in mailItems)
             {
                 listBox1.Items.Remove(mailItem);
             }
         }
     }
     catch (Exception ex) {
         Text = "rozłączono";
     }
 }