diff --git a/src/main/java/de/neemann/digital/analyse/expression/modify/NAnd.java b/src/main/java/de/neemann/digital/analyse/expression/modify/NAnd.java
index 5f0c75a89..91a5ce08c 100644
--- a/src/main/java/de/neemann/digital/analyse/expression/modify/NAnd.java
+++ b/src/main/java/de/neemann/digital/analyse/expression/modify/NAnd.java
@@ -1,6 +1,7 @@
 package de.neemann.digital.analyse.expression.modify;
 
 import de.neemann.digital.analyse.expression.Expression;
+import de.neemann.digital.analyse.expression.Not;
 import de.neemann.digital.analyse.expression.Operation;
 
 import java.util.ArrayList;
@@ -14,7 +15,9 @@ public class NAnd implements ExpressionModifier {
 
     @Override
     public Expression modify(Expression expression) {
-        if (expression instanceof Operation.Or) {
+        if (expression instanceof Operation.And) {
+            return new Not(not(expression));
+        } else if (expression instanceof Operation.Or) {
             ArrayList<Expression> exp = new ArrayList<>();
             for (Expression e : ((Operation.Or) expression).getExpressions())
                 exp.add(not(e));
diff --git a/src/main/java/de/neemann/digital/analyse/expression/modify/NOr.java b/src/main/java/de/neemann/digital/analyse/expression/modify/NOr.java
index a9766bc99..0365ced84 100644
--- a/src/main/java/de/neemann/digital/analyse/expression/modify/NOr.java
+++ b/src/main/java/de/neemann/digital/analyse/expression/modify/NOr.java
@@ -1,6 +1,7 @@
 package de.neemann.digital.analyse.expression.modify;
 
 import de.neemann.digital.analyse.expression.Expression;
+import de.neemann.digital.analyse.expression.Not;
 import de.neemann.digital.analyse.expression.Operation;
 
 import java.util.ArrayList;
@@ -14,6 +15,9 @@ public class NOr implements ExpressionModifier {
 
     @Override
     public Expression modify(Expression expression) {
+        if (expression instanceof Operation.Or) {
+            return new Not(not(expression));
+        } else
         if (expression instanceof Operation.And) {
             ArrayList<Expression> exp = new ArrayList<>();
             for (Expression e : ((Operation.And) expression).getExpressions())
diff --git a/src/main/java/de/neemann/digital/draw/builder/Builder.java b/src/main/java/de/neemann/digital/draw/builder/Builder.java
index 5f9caf465..d27760e0e 100644
--- a/src/main/java/de/neemann/digital/draw/builder/Builder.java
+++ b/src/main/java/de/neemann/digital/draw/builder/Builder.java
@@ -172,6 +172,7 @@ public class Builder {
      */
     public Circuit createCircuit() {
         createInputBus();
+        circuit.setNotModified();
         return circuit;
     }
 
diff --git a/src/main/java/de/neemann/digital/draw/elements/Circuit.java b/src/main/java/de/neemann/digital/draw/elements/Circuit.java
index 348fda350..38cb1f71e 100644
--- a/src/main/java/de/neemann/digital/draw/elements/Circuit.java
+++ b/src/main/java/de/neemann/digital/draw/elements/Circuit.java
@@ -383,6 +383,13 @@ public class Circuit {
         modified = true;
     }
 
+    /**
+     * Sets this circuits state to not modified
+     */
+    public void setNotModified() {
+        modified = false;
+    }
+
     /**
      * @return true if modified
      */
diff --git a/src/main/java/de/neemann/digital/gui/components/table/TableFrame.java b/src/main/java/de/neemann/digital/gui/components/table/TableFrame.java
index 40902c5de..613aa9dd0 100644
--- a/src/main/java/de/neemann/digital/gui/components/table/TableFrame.java
+++ b/src/main/java/de/neemann/digital/gui/components/table/TableFrame.java
@@ -8,6 +8,7 @@ import de.neemann.digital.analyse.expression.format.FormatToExpression;
 import de.neemann.digital.analyse.expression.format.FormatterException;
 import de.neemann.digital.analyse.expression.modify.ExpressionModifier;
 import de.neemann.digital.analyse.expression.modify.NAnd;
+import de.neemann.digital.analyse.expression.modify.NOr;
 import de.neemann.digital.draw.builder.Builder;
 import de.neemann.digital.draw.builder.BuilderException;
 import de.neemann.digital.draw.elements.Circuit;
@@ -133,12 +134,12 @@ public class TableFrame extends JFrame {
                 createCircuit(new NAnd());
             }
         }.setToolTip(Lang.get("menu_table_createNAnd_tt")).createJMenuItem());
-//        createMenu.add(new ToolTipAction(Lang.get("menu_table_createNOr")) {
-//            @Override
-//            public void actionPerformed(ActionEvent actionEvent) {
-//                createCircuit(new NOr());
-//            }
-//        }.setToolTip(Lang.get("menu_table_createNOr_tt")).createJMenuItem());
+        createMenu.add(new ToolTipAction(Lang.get("menu_table_createNOr")) {
+            @Override
+            public void actionPerformed(ActionEvent actionEvent) {
+                createCircuit(new NOr());
+            }
+        }.setToolTip(Lang.get("menu_table_createNOr_tt")).createJMenuItem());
 
         bar.add(createMenu);
 
diff --git a/src/main/resources/lang/lang_de.properties b/src/main/resources/lang/lang_de.properties
index 6ca28f6f4..79838ab82 100644
--- a/src/main/resources/lang/lang_de.properties
+++ b/src/main/resources/lang/lang_de.properties
@@ -270,6 +270,8 @@ menu_table_create=Model erzeugen
 menu_table_create_tt=Erzeugt ein Model, welches der Wahrheitstabelle entspricht.
 menu_table_createNAnd=Model erzeugen mit NAnd
 menu_table_createNAnd_tt=Erzeugt ein Model, welches der Wahrheitstabelle entspricht nur mit NAnd-Gattern.
+menu_table_createNOr=Model erzeugen mit NOr
+menu_table_createNOr_tt=Erzeugt ein Model, welches der Wahrheitstabelle entspricht nur mit NOr-Gattern.
 
 menu_about=\u00DCber Digital
 
diff --git a/src/main/resources/lang/lang_en.properties b/src/main/resources/lang/lang_en.properties
index 45e5e9f49..59382632a 100644
--- a/src/main/resources/lang/lang_en.properties
+++ b/src/main/resources/lang/lang_en.properties
@@ -250,6 +250,8 @@ menu_table_create=create circuit
 menu_table_create_tt=Creates a circuit which reproduces the truth table.
 menu_table_createNAnd=create with NAnd
 menu_table_createNAnd_tt=Creates a circuit which reproduces the truth table only with NAnd gates.
+menu_table_createNOr=create with NOr
+menu_table_createNOr_tt=Creates a circuit which reproduces the truth table only with NOr gates.
 
 win_saveChanges=Save Changes?
 win_confirmExit=Confirm Exit!