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. For example, action of Shift-Ctl-F10 may only be defined by the user if F10_IS_MENU is set to "0", otherwise this key combination activates context menus. This variable does not affect the behavior of the mouse. However, the mouse continues to work with the menu.