Fix for disabling the Item stacking feature.

src/main/java/com/songoda/ultimatestacker/listeners/ItemListeners.java

@@ -31,10 +31,10 @@ public class ItemListeners implements Listener {
 
     @EventHandler
     public void onMerge(ItemMergeEvent event) {
-        event.setCancelled(true);
-
         int maxItemStackSize = Setting.MAX_STACK_ITEMS.getInt();
         if (!Setting.STACK_ITEMS.getBoolean()) return;
+        
+        event.setCancelled(true);
 
         Item item = event.getTarget();