PRB: OLE Controls May Be Hidden by Group Box in Dialog

The information in this article applies to:

• Microsoft Visual C++, 32-bit Edition, version 4.0

SYMPTOMS

OLE controls may be covered by a group box if the group box precedes the OLE control in the tab order. In the case of an OLE Control that subclasses an edit control -- 3D look enabled only -- the control's border will be drawn but the control itself will not be visible, and the control will appear to be disabled.

CAUSE

The tab order in a dialog is synonymous with the Z order, meaning that a control that is first in the tab order will have a higher Z order than a control that follows it in the Z order. A control with the WS_CLIPSIBLINGS window style set that is overlapped by another control will not be painted in the area that is overlapped. OLE controls have the WS_CLIPSIBLINGS window style set by default.

RESOLUTION

Set the tab order position of the group box to be later in the tab order than the controls it contains. This can be done without affecting the physical tab order of the dialog.

STATUS

This behavior is by design.

MORE INFORMATION

Standard window's controls typically do not have the WS_CLIPSIBLINGS window style set. However, any control that does have the WS_CLIPSIBLINGS window style set will behave as described here. In the case of OLE controls, WS_CLIPSIBLINGS is set by default. This being the case, this behavior will be noticed any time an OLE control is placed in a group box and the group box precedes the control in the tab order.