In Windows, a combination box consists of an edit control, which is a child of the combination box control and a list box control, which is a child of the Desktop window. When the list box is dropped, the list box becomes a child of the combination box and reverts to being a child of the Desktop when it is closed.
In Open32, a combination box consists of an edit control, which is a child of the combination box control and a list box control which is a child of the object window. When the list box is dropped, the list box becomes a child of the combination box and reverts to being a child of the root object window when it is closed.
You will need to slightly modify application code to enumerate and find a combination list box control in Windows. For the starting parameter in your enumeration routines, use the following for each platform:
Windows
When creating an Open32 window that will have combination box children, do not use the CLIPCHILDREN flag.