Thanks Mike for your response.

I forgot to mention I am working with an application that uses Version 2010 Vol 3. I am afraid I don't have the freedom to upgrade the component library version.

So my hope to achieve this is to develop custom control wrapping this control and a textbox.

Do you see any other options ?

We did implement it as a feature a while ago, so honestly the best way would be to just upgrade. But you could remove the tabstop from the control to keep users from tabbing into it for editing. For clicking into it you can use the following:

private void ultraDateTimeEditor1_MouseDown(object sender, MouseEventArgs e)
{
 UltraDateTimeEditor dtEditor = sender as UltraDateTimeEditor;
 UIElement uiClicked = dtEditor.UIElement.ElementFromPoint(e.Location);
 if (!(uiClicked is DateTimeEditorDropDownButtonUIElement))
  dtEditor.Editor.ExitEditMode(true, true);

}

private void ultraDateTimeEditor1_AfterCloseUp(object sender, EventArgs e)
{
 UltraDateTimeEditor dtEditor = sender as UltraDateTimeEditor;
 dtEditor.Editor.ExitEditMode(true, true);
}

Let me know if that helps,