By convention, the F10 key is used by Windows and Windows NT to activate program menus. This action is controlled automatically by the program. The F10_IS_MENU configuration variable allows you to set the runtime to handle the F10 key as a user defined key. The default setting is "1" (on, true, yes). When you change the setting to "0" (off, false, no) you inhibit the menu activation capability. The mouse continues, however, to work with the menu.