Paraphrasing from the help file, plus my own input:

The Shapes collection is a collection of all shape objects that exist in the drawing layer e.g. autoshape, freeform, OLE Object, picture. ActiveX controls are OLE objects and therefore included as part of the Shapes collections.

The OLEObjects collection is a collection of all ActiveX controls or embedded objects (e.g. an embedded Powerpoint presentation) on a worksheet.

Therefore, ActiveX controls are members of both the Shapes collection AND the OLEObjects collection.

HTH,
Dan