Handles SHIFT+F1 Help for in-place items.
To enable context-sensitive help, you must add an
statement to your CFrameWnd class message map and also add an accelerator-table entry, typically SHIFT+F1, to enable this member function.
If your application is an OLE Container, OnContextHelp puts all in-place items contained within the frame window object into Help mode. The cursor changes to an arrow and a question mark, and the user can then move the mouse pointer and press the left mouse button to select a dialog box, window, menu, or command button. This member function calls the Windows function WinHelp with the Help context of the object under the cursor.