In order to provide help, the application must associate an instance of the Help Manager with a chain of application windows. This association lets the Help Manager know which instance should provide the help function.

The Help Manager traces the window chain, starting from the window where help is requested. The application window in the chain with the associated help instance will be the one with which the Help Manager communicates and next to which the help window is positioned, unless a HM_SET_ACTIVE_WINDOW message is sent to the Help Manager. If the HM_SET_ACTIVE_WINDOW message is sent to the Help Manager, the active window parameter is the window with which the Help Manager communicates. The Help Manager positions the help window next to the window specified as the relative window.