help-menu:about-callback in drscheme:frame:basics-mixin

This method is called when the about menu-item of the help-menu menu is selected.

• (send a-drscheme:frame:basics-mixin help-menu:about-callback item evt) -> void
     item : (instance (derived-from menu-item%))
     evt : (instance control-event%)

  Opens an about box for DrScheme.