The menu control window procedure responds to this message by setting the selection state of the (sub)menu which contains the specified item to indicate that the item is selected or deselected. If usincludesubmenus is set to TRUE, the selection state of the (sub)menu owning the submenu which contains the specified item is also set. This process continues up the menu hierarchy until the top level menu is reached.
If an item is selected, and usdismissed is set to TRUE, a WM_COMMAND, WM_SYSCOMMAND, or WM_HELP message, as appropriate, is posted to the owner, and the menu is dismissed.
Note: This message must be sent, not posted, to the menu control.