Added DEFGENERIC form for SCROLLER-PANE/HORIZONTAL-DRAG-CALLBACK.
Added DEFGENERIC form for SCROLLER-PANE/HORIZONTAL-DRAG-CALLBACK.

onixie/mcclim,slyrus/mcclim,swflint/McCLIM,swflint/McCLIM,slyrus/mcclim,onixie/mcclim,onixie/mcclim,swflint/McCLIM