diff --git a/BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/simulator/gui/SimulatorMaterialGui.java b/BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/simulator/gui/SimulatorMaterialGui.java
index 84f1e682..f081374d 100644
--- a/BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/simulator/gui/SimulatorMaterialGui.java
+++ b/BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/simulator/gui/SimulatorMaterialGui.java
@@ -53,6 +53,16 @@ public class SimulatorMaterialGui extends SimulatorPageGui<Material> {
         this.back = back;
     }
 
+    @Override
+    public boolean shouldOpen() {
+        if (player.getItemOnCursor().getType().isAir()) {
+            return true;
+        }
+        change.accept(player.getItemOnCursor().getType());
+        SimulatorWatcher.update(simulator);
+        return false;
+    }
+
     @Override
     public String baseTitle() {
         return "Material";
diff --git a/BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/simulator/gui/base/SimulatorBaseGui.java b/BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/simulator/gui/base/SimulatorBaseGui.java
index e3ddd797..6fa35d4c 100644
--- a/BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/simulator/gui/base/SimulatorBaseGui.java
+++ b/BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/simulator/gui/base/SimulatorBaseGui.java
@@ -46,6 +46,8 @@ public abstract class SimulatorBaseGui {
     }
 
     public final void open() {
+        if (!shouldOpen()) return;
+
         String newTitle = title();
         String originalTitle = player.getOpenInventory().getTitle();
 
@@ -86,6 +88,10 @@ public abstract class SimulatorBaseGui {
         inventory.open();
     }
 
+    public boolean shouldOpen() {
+        return true;
+    }
+
     private void setup() {
         for (int i = 0; i < 9; i++) {
             inventory.setItem(i, new SWItem(Material.GRAY_STAINED_GLASS_PANE, "§8", clickType -> {