yes,this is my modif start at linenums 310
if(hor) {
//knob_area->x1 -= (knob_size >> 1);
knob_area->x1 -= (knob_size );
if (knob_area->x1 < obj->coords.x1)
knob_area->x1 = obj->coords.x1;
knob_area->x2 = knob_area->x1 + knob_size - 1;
knob_area->y1 = obj->coords.y1;
knob_area->y2 = obj->coords.y2;
}
else {
// knob_area->y1 -= (knob_size >> 1);
knob_area->y1 -= (knob_size );