Sign edit only with Empty hand

BauSystem_Main/src/de/steamwar/bausystem/world/RegionListener.java

@@ -32,6 +32,7 @@ import de.steamwar.core.VersionedRunnable;
 import org.bukkit.Bukkit;
 import org.bukkit.ChatColor;
 import com.comphenix.protocol.ProtocolLibrary;
+import org.bukkit.Material;
 import org.bukkit.block.Block;
 import org.bukkit.block.Sign;
 import org.bukkit.entity.Player;
@@ -115,7 +116,9 @@ public class RegionListener implements Listener {
     public void editSign(PlayerInteractEvent event) {
         if(event.getAction() != Action.RIGHT_CLICK_BLOCK ||
                 !event.getClickedBlock().getType().name().contains("SIGN") ||
-                !event.getPlayer().isSneaking())
+                !event.getPlayer().isSneaking() ||
+                event.getItem() == null ||
+                event.getItem().getType() != Material.AIR)
             return;
 
         Player player = event.getPlayer();