Labeling Owner-Drawn Controls
Application developers should define a label, also known as caption text, for all owner-drawn controls, even if the label is not visible on the screen. The label must come immediately before the control that it is labeling, and must be in the next item in the tab order.
For example, if you define a label when creating an owner-drawn button in which a graphic is displayed instead of the normal caption text, client applications get the label and use it to identify the control.
For more information about exposing owner-drawn controls and menus, see: