private void tabs_TabClosing(object sender, CancelSourceEventArgs e)
 {
     if (!_closing)
     {
         _closing = true;
         C1TabItem tabItem = (C1TabItem)e.Source;
         e.Cancel = true;
         MessageBoxResult result = MessageBox.Show("Do you really want to close this tab?", "Close Tabs?", MessageBoxButton.YesNo, MessageBoxImage.Question);
         if (result == MessageBoxResult.Yes)
         {
             c1Tab.Items.Remove(tabItem);
         }
         _closing = false;
     }
 }
 private void tabs_TabClosing(object sender, CancelSourceEventArgs e)
 {
     if (!_closing)
     {
         _closing = true;
         C1TabItem tabItem = (C1TabItem)e.Source;
         e.Cancel = true;
         MessageBoxResult result = MessageBox.Show("Do you really want to close this tab?", "Close Tabs?", MessageBoxButton.YesNo, MessageBoxImage.Question);
         if (result == MessageBoxResult.Yes)
         {
             c1Tab.Items.Remove(tabItem);
         }
         _closing = false;
     }
 }