The code for displaying the Viewer History list (controlled by the IDM_HISTORY message) resembles the code for jumping to a context string, but it is even simpler. The call to MVAPI hard-codes the Viewer command, History, that displays the History list as follows:
case IDM_HISTORY:
CheckLoadUsa(hwnd) ;
MVAPI(hwnd, BookPath,cmdMacro, (DWORD)(LPSTR) "History()");
return 0 ;
This same mechanism is used by Next (IDM_NEXT message, Next() command), Prev (IDM_PREV message, Prev() command), and CopyTopic (IDM_COPYTOPIC message, CopyTopic() command) on the Viewer menu.