Prevent players from dropping items

src/de/anura/core/Setup.java

@@ -13,6 +13,7 @@ import de.anura.core.events.BlockBreak;
 import de.anura.core.events.BlockPlace;
 import de.anura.core.events.BlockSpread;
 import de.anura.core.events.CmdPreprocess;
+import de.anura.core.events.DropItem;
 import de.anura.core.events.EntityDamage;
 import de.anura.core.events.EntityDamageByE;
 import de.anura.core.events.FoodChange;
@@ -83,6 +84,7 @@ public class Setup {
         new PlayerTeleport(Core.getMainClass());
         new InvClick(Core.getMainClass());
         new BlockSpread(Core.getMainClass());
+        new DropItem(Core.getMainClass());
     }
 
     public static void setupClasses() {

src/de/anura/core/events/DropItem.java

@@ -0,0 +1,29 @@
+package de.anura.core.events;
+
+import de.anura.core.AnuraCore;
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerDropItemEvent;
+
+public class DropItem implements Listener {
+
+    public DropItem(AnuraCore plugin) {
+        plugin.getServer().getPluginManager().registerEvents(this, plugin);
+    }
+
+    @EventHandler
+    public void onPlayerDropItem(PlayerDropItemEvent event) {
+        if (AnuraCore.getInstance().getConfig().getBoolean("is-main-lobby") && !event.getPlayer().hasPermission("core.inventory.interact")) {
+            event.setCancelled(true);
+            final Player P = event.getPlayer();
+            Bukkit.getScheduler().scheduleSyncDelayedTask(AnuraCore.getInstance(), new Runnable() {
+                @Override
+                public void run() {
+                    P.updateInventory();
+                }
+            }, 2);
+        }
+    }
+}