file-menu:new-callback in drscheme:frame:basics-mixin
This method is called when the new menu-item of the file-menu menu is selected.
(voidsenda-drscheme:frame:basics-mixinfile-menu:new-callbackitemevt
item: (instance (derived-frommenu-item%))
evt: (instancecontrol-event%)Opens a new, empty DrScheme window.