Hi Kevin,

>I don't see anything wrong with the code you've posted...this IS strange behavior. How about posting the code you've put in the subclass you've created...there might be something we can see in that.

The code of the subclassed control is just inheriting from the SyncFusion CheckBoxAdv and the ImmBindingList and ImmUISecurity interfaces. The same as for the mmComboBox.

public class OurComboBoxAdv : Syncfusion.Windows.Forms.Tools.ComboBoxAdv, ImmBindingList, ImmUISecurity

In the body of the subclassed control are the implementations of ImmUISecurity, ImmBinding, ImmBindingList interfaces, the override of the OnPaint and Text method and property respectively, which is copied from the mmComboBox.cs file. Besides the default (empty) constructor there is this one :

public OurComboBoxAdv(System.ComponentModel.IContainer container)
{
///
/// Required for Windows.Forms Class Composition Designer support
///
   container.Add(this);
   InitializeComponent();

//
// TODO: Add any constructor code after InitializeComponent call
//
}

Regards

-Filip