I'm trying to create a custom dropdown for a derivative of CComboBox. The dropdown will be a calendar control plus some 'hotspots', e.g.

So I figure the best way to achieve this is to have a simple CWnd-derived class which acts as the parent to the calendar control, and have it paint the hotspots itself.

The window needs to be a popup window - I think - rather than a child window so that it isn't clipped. But doing this causes the dialog (on which the combobox control is placed) to stop being the topmost (foreground?) window, leading to its frame being drawn differently:

This spoils the illusion that the dropdown is part of the combobox since its acting more like a modal dialog at this point. Any suggestions on how I make the custom dropdown behave like the regular dropdown?

Are there any other pitfalls I need to watch out for, e.g. focus and mouse capture issues?