Windowless
Controls
The ActiveX
Controls 96 specification includes a definition for windowless controls. Such
controls do not operate in their own window and require a container to offer a
shared window into which the control may draw, see the ActiveX SDK. Windowless
controls are designed to be compatible with older control containers by
creating their own window in that situation, windowless control containers
should host windowed controls in the traditional way with no problem. It may
however be useful for a container to distinguish those controls that can
operate in a windowless mode, so an appropriate component category is defined.
CATID - { 1D06B600-3AE3-11cf-87B9-00AA006C8166}
CATID_WindowlessObject