@ForgeSubscribe
  public void onPlayerFall(LivingFallEvent event) {

    event.setCanceled(event.entity.worldObj.provider.dimensionId == mod_pocketDim.limboDimID);
  }
 @ForgeSubscribe
 public void onEvent(LivingFallEvent evt) {
   if (evt.isCancelable()) {
     evt.setCanceled(true);
   }
 }