When a page is activated, the property sheet determines whether to enable or disable the Help button for the page by checking for the PSP_HASHELP style. If the page has this style, it supports the Help button. If the PSP_HASHELP style is not present, the button is disabled.
When the user chooses the Help button, the active page receives the PSN_HELP notification message. The page should respond by displaying help information, typically by calling the WinHelp function.