introduced a separate color (red) to indicate errors

src/main/java/de/neemann/digital/draw/elements/Circuit.java

@@ -170,17 +170,18 @@ public class Circuit {
      * @param graphic the graphic instance used
      */
     public void drawTo(Graphic graphic) {
-        drawTo(graphic, EMPTY_SET, NoSync.INST);
+        drawTo(graphic, EMPTY_SET, null, NoSync.INST);
     }
 
     /**
-     * Draws tis circuit using the given graphic instance
+     * Draws this circuit using the given graphic instance
      *
      * @param graphic     the graphic instance used
      * @param highLighted a list of Drawables to highlight
+     * @param highlight   style used to draw the highlighted elements
      * @param modelSync   sync interface to access the model. Is locked while drawing circuit
      */
-    public void drawTo(Graphic graphic, Collection<Drawable> highLighted, Sync modelSync) {
+    public void drawTo(Graphic graphic, Collection<Drawable> highLighted, Style highlight, Sync modelSync) {
         if (!dotsPresent) {
             new DotCreator(wires).applyDots();
             dotsPresent = true;
@@ -189,11 +190,11 @@ public class Circuit {
         modelSync.access(() -> {
             graphic.openGroup();
             for (Wire w : wires)
-                w.drawTo(graphic, highLighted.contains(w));
+                w.drawTo(graphic, highLighted.contains(w) ? highlight : null);
             graphic.closeGroup();
             for (VisualElement p : visualElements) {
                 graphic.openGroup();
-                p.drawTo(graphic, highLighted.contains(p));
+                p.drawTo(graphic, highLighted.contains(p) ? highlight : null);
                 graphic.closeGroup();
             }
         });
@@ -640,9 +641,9 @@ public class Circuit {
      * @param circuit the circuit to take the listeners from
      */
     public void getListenersFrom(Circuit circuit) {
-        if (circuit.listeners!=null) {
+        if (circuit.listeners != null) {
-            if (listeners==null)
+            if (listeners == null)
-                listeners=new ArrayList<>();
+                listeners = new ArrayList<>();
             listeners.addAll(circuit.listeners);
         }
     }

src/main/java/de/neemann/digital/draw/elements/VisualElement.java

@@ -61,7 +61,7 @@ public class VisualElement implements Drawable, Movable, AttributeListener {
         this.elementName = proto.elementName;
         this.elementAttributes = new ElementAttributes(proto.elementAttributes);
         setPos(new Vector(proto.pos));
-        this.shapeFactory=proto.shapeFactory;
+        this.shapeFactory = proto.shapeFactory;
     }
 
     /**
@@ -165,19 +165,19 @@ public class VisualElement implements Drawable, Movable, AttributeListener {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         drawShape(graphic, highLight);
 
         // draw circle around element
-        if (highLight) {
+        if (highLight != null) {
             GraphicMinMax mm = getMinMax(false);
             Vector delta = mm.getMax().sub(mm.getMin()).add(SIZE, SIZE).div(2);
             Vector pos = mm.getMax().add(mm.getMin()).div(2);
-            graphic.drawCircle(pos.sub(delta), pos.add(delta), Style.HIGHLIGHT);
+            graphic.drawCircle(pos.sub(delta), pos.add(delta), highLight);
         }
     }
 
-    private void drawShape(Graphic graphic, boolean highLight) {
+    private void drawShape(Graphic graphic, Style highLight) {
         Graphic gr = new GraphicTransform(graphic, createTransform());
         Shape shape = getShape();
         shape.drawTo(gr, highLight);
@@ -205,14 +205,14 @@ public class VisualElement implements Drawable, Movable, AttributeListener {
         if (includeText) {
             if (minMaxText == null) {
                 GraphicMinMax mm = new GraphicMinMax(true);
-                drawShape(mm, false);
+                drawShape(mm, null);
                 minMaxText = mm;
             }
             return minMaxText;
         } else {
             if (minMax == null) {
                 GraphicMinMax mm = new GraphicMinMax(false);
-                drawShape(mm, false);
+                drawShape(mm, null);
                 minMax = mm;
             }
             return minMax;
@@ -246,7 +246,7 @@ public class VisualElement implements Drawable, Movable, AttributeListener {
      */
     public BufferedImage getBufferedImage(double scale, int maxHeight) {
         GraphicMinMax mm = new GraphicMinMax();
-        drawShape(mm, false);
+        drawShape(mm, null);
 
         if (mm.getMax().y - mm.getMin().y > maxHeight / scale)
             scale = (double) (maxHeight - 1) / (mm.getMax().y - mm.getMin().y + 4);
@@ -266,7 +266,7 @@ public class VisualElement implements Drawable, Movable, AttributeListener {
         gr.scale(scale, scale);
         gr.translate(2 - mm.getMin().x, 2 - mm.getMin().y);
         GraphicSwing grs = new GraphicSwing(gr);
-        drawTo(grs, false);
+        drawTo(grs, null);
         return bi;
     }
 

src/main/java/de/neemann/digital/draw/elements/Wire.java

@@ -55,9 +55,9 @@ public class Wire implements Drawable, Movable {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
-        Style style = Style.HIGHLIGHT;
+        Style style = highLight;
-        if (!highLight)
+        if (style == null)
             style = Style.getWireStyle(value);
 
         graphic.drawLine(p1, p2, style);

src/main/java/de/neemann/digital/draw/graphics/Style.java

@@ -84,6 +84,11 @@ public class Style {
      */
     public static final Style HIGHLIGHT = new Style(WIRETHICK, false, Color.CYAN);
 
+    /**
+     * error color used for the circles to mark an element
+     */
+    public static final Style ERROR = new Style(WIRETHICK, false, Color.RED.darker());
+
     private final int thickness;
     private final boolean filled;
     private final Color color;
@@ -180,4 +185,5 @@ public class Style {
         if (value.getValueIgnoreBurn() == 1) return WIRE_HIGH;
         else return WIRE_LOW;
     }
+
 }

src/main/java/de/neemann/digital/draw/shapes/BreakShape.java

@@ -48,7 +48,7 @@ public class BreakShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         Vector center = new Vector(2 + SIZE, 0);
         graphic.drawCircle(center.sub(RAD), center.add(RAD), Style.NORMAL);
         graphic.drawLine(center.sub(D1), center.add(D1), Style.NORMAL);

src/main/java/de/neemann/digital/draw/shapes/ButtonShape.java

@@ -83,7 +83,7 @@ public class ButtonShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         boolean down = false;
         if (ioState != null) down = ioState.getOutput(0).getBool();
 

src/main/java/de/neemann/digital/draw/shapes/ClockShape.java

@@ -70,7 +70,7 @@ public class ClockShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         graphic.drawPolygon(new Polygon(true)
                 .add(-SIZE * 2 - 1, -SIZE)
                 .add(-1, -SIZE)

src/main/java/de/neemann/digital/draw/shapes/ConstShape.java

@@ -45,7 +45,7 @@ public class ConstShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         Vector textPos = new Vector(-3, 0);
         graphic.drawText(textPos, textPos.add(1, 0), value, Orientation.RIGHTCENTER, Style.NORMAL);
     }

src/main/java/de/neemann/digital/draw/shapes/DILShape.java

@@ -67,7 +67,7 @@ public class DILShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         int dp = SPACING * SIZE;
         int pin = dp / 4;
         int x = width * SIZE;

src/main/java/de/neemann/digital/draw/shapes/DataShape.java

@@ -10,6 +10,7 @@ import de.neemann.digital.core.element.PinDescriptions;
 import de.neemann.digital.draw.elements.IOState;
 import de.neemann.digital.draw.elements.Pins;
 import de.neemann.digital.draw.graphics.Graphic;
+import de.neemann.digital.draw.graphics.Style;
 import de.neemann.digital.draw.model.ModelCreator;
 import de.neemann.digital.draw.model.ModelEntry;
 import de.neemann.digital.gui.components.CircuitComponent;
@@ -61,11 +62,11 @@ public class DataShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         if (dataSet == null) {
             dataSet = new DataSet();
         }
-        dataSet.drawTo(graphic, false);
+        dataSet.drawTo(graphic, null);
     }
 
     @Override

src/main/java/de/neemann/digital/draw/shapes/DelayShape.java

@@ -41,7 +41,7 @@ public class DelayShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         graphic.drawPolygon(
                 new Polygon(true)
                         .add(1, -SIZE2)

src/main/java/de/neemann/digital/draw/shapes/DemuxerShape.java

@@ -65,7 +65,7 @@ public class DemuxerShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawPolygon(new Polygon(true)
                 .add(1, 5)
                 .add(SIZE * 2 - 1, -4)

src/main/java/de/neemann/digital/draw/shapes/DiodeBackwardShape.java

@@ -50,7 +50,7 @@ public class DiodeBackwardShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         Style style = blown ? Style.DASH : Style.NORMAL;
 
         graphic.drawPolygon(

src/main/java/de/neemann/digital/draw/shapes/DiodeForewardShape.java

@@ -50,7 +50,7 @@ public class DiodeForewardShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         Style style = blown ? Style.DASH : Style.NORMAL;
 
         graphic.drawPolygon(

src/main/java/de/neemann/digital/draw/shapes/DiodeShape.java

@@ -48,7 +48,7 @@ public class DiodeShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         Style style = blown ? Style.DASH : Style.NORMAL;
 
         graphic.drawPolygon(

src/main/java/de/neemann/digital/draw/shapes/Drawable.java

@@ -1,6 +1,7 @@
 package de.neemann.digital.draw.shapes;
 
 import de.neemann.digital.draw.graphics.Graphic;
+import de.neemann.digital.draw.graphics.Style;
 
 /**
  * Interface implemented by the elements which can draw itself to a {@link Graphic} instance.
@@ -10,9 +11,8 @@ import de.neemann.digital.draw.graphics.Graphic;
 public interface Drawable {
     /**
      * Draws an element depending on its state.
-     *
+     *  @param graphic   interface to draw to
-     * @param graphic   interface to draw to
      * @param highLight true if a highlighted drawing is required
      */
-    void drawTo(Graphic graphic, boolean highLight);
+    void drawTo(Graphic graphic, Style highLight);
 }

src/main/java/de/neemann/digital/draw/shapes/DriverShape.java

@@ -70,7 +70,7 @@ public class DriverShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawPolygon(
                 new Polygon(true)
                         .add(-SIZE + 1, -SIZE2 - 2)

src/main/java/de/neemann/digital/draw/shapes/FETShape.java

@@ -51,7 +51,7 @@ public abstract class FETShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         final int g = SIZE2 / 2;
         graphic.drawPolygon(new Polygon(false)
                 .add(SIZE, 0)

src/main/java/de/neemann/digital/draw/shapes/FETShapeN.java

@@ -37,7 +37,7 @@ public class FETShapeN extends FETShape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         super.drawTo(graphic, highLight);
 
         // the arrow

src/main/java/de/neemann/digital/draw/shapes/FETShapeP.java

@@ -38,7 +38,7 @@ public class FETShapeP extends FETShape {
 
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         super.drawTo(graphic, highLight);
 
         // the arrow

src/main/java/de/neemann/digital/draw/shapes/FGFETShapeN.java

@@ -45,7 +45,7 @@ public class FGFETShapeN extends FETShape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         super.drawTo(graphic, highLight);
 
         if (programmed)

src/main/java/de/neemann/digital/draw/shapes/FGFETShapeP.java

@@ -44,7 +44,7 @@ public class FGFETShapeP extends FETShape {
 
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         super.drawTo(graphic, highLight);
 
         if (programmed)

src/main/java/de/neemann/digital/draw/shapes/GenericShape.java

@@ -171,7 +171,7 @@ public class GenericShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         int max = Math.max(inputs.size(), outputs.size());
         int height = (max - 1) * SIZE + SIZE2;
 

src/main/java/de/neemann/digital/draw/shapes/GroundShape.java

@@ -43,7 +43,7 @@ public class GroundShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         graphic.drawLine(new Vector(-SIZE2, 0), new Vector(SIZE2, 0), Style.THICK);
     }
 }

src/main/java/de/neemann/digital/draw/shapes/InputShape.java

@@ -88,7 +88,7 @@ public class InputShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         Style style = Style.NORMAL;
         if (ioState != null) {
             ObservableValue value = ioState.getOutput(0);

src/main/java/de/neemann/digital/draw/shapes/LEDShape.java

@@ -54,7 +54,7 @@ public class LEDShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         boolean fill = true;
         if (ioState != null) {
             fill = false;

src/main/java/de/neemann/digital/draw/shapes/LightBulbShape.java

@@ -12,8 +12,6 @@ import de.neemann.digital.draw.graphics.Graphic;
 import de.neemann.digital.draw.graphics.Style;
 import de.neemann.digital.draw.graphics.Vector;
 
-import java.awt.*;
-
 import static de.neemann.digital.draw.shapes.GenericShape.SIZE;
 
 /**
@@ -56,7 +54,7 @@ public class LightBulbShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         if (a != null && b != null) {
             boolean on = !a.isHighZ() && !b.isHighZ() && (a.getBool() != b.getBool());
             if (on)

src/main/java/de/neemann/digital/draw/shapes/MissingShape.java

@@ -42,7 +42,7 @@ public class MissingShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         Style style = Style.NORMAL_TEXT;
         graphic.drawText(new Vector(4, 4), new Vector(5, 4), message, Orientation.LEFTTOP, style);
         if (cause != null && cause.length() > 0)

src/main/java/de/neemann/digital/draw/shapes/MuxerShape.java

@@ -60,7 +60,7 @@ public class MuxerShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         graphic.drawPolygon(new Polygon(true)
                 .add(1, -4)
                 .add(SIZE * 2 - 1, 5)

src/main/java/de/neemann/digital/draw/shapes/OutputShape.java

@@ -63,7 +63,7 @@ public class OutputShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         Style style = Style.NORMAL;
         if (ioState != null) {
             ObservableValue value = ioState.getInput(0);

src/main/java/de/neemann/digital/draw/shapes/ProbeShape.java

@@ -58,7 +58,7 @@ public class ProbeShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawText(new Vector(2, -1), new Vector(3, -1), label, Orientation.LEFTBOTTOM, Style.NORMAL);
         if (bits > 1) {
             String v = format.format(inValue);

src/main/java/de/neemann/digital/draw/shapes/PullDownShape.java

@@ -53,7 +53,7 @@ public class PullDownShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawPolygon(
                 new Polygon(true)
                         .add(-WIDTH2, 1)

src/main/java/de/neemann/digital/draw/shapes/PullUpShape.java

@@ -47,7 +47,7 @@ public class PullUpShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawPolygon(
                 new Polygon(true)
                         .add(-WIDTH2, -1)

src/main/java/de/neemann/digital/draw/shapes/RelayShape.java

@@ -56,7 +56,7 @@ public class RelayShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         int yOffs = 0;
 
         boolean closed = invers;

src/main/java/de/neemann/digital/draw/shapes/ResetShape.java

@@ -44,7 +44,7 @@ public class ResetShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawPolygon(new Polygon(true).add(-SIZE * 2 - 2, -SIZE).add(-2, -SIZE).add(-2, SIZE).add(-SIZE * 2 - 2, SIZE), Style.NORMAL);
 
         Vector textPos = new Vector(-SIZE * 2 + 2, -SIZE + 2);

src/main/java/de/neemann/digital/draw/shapes/RotEncoderShape.java

@@ -106,7 +106,7 @@ public class RotEncoderShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         graphic.drawPolygon(new Polygon(true)
                 .add(0, -SIZE)
                 .add(0, SIZE * 2)

src/main/java/de/neemann/digital/draw/shapes/SevenSegShape.java

@@ -74,7 +74,7 @@ public class SevenSegShape extends SevenShape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         super.drawTo(graphic, highLight);
         if (commonCatode)
             graphic.drawLine(

src/main/java/de/neemann/digital/draw/shapes/SevenShape.java

@@ -67,7 +67,7 @@ public abstract class SevenShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawPolygon(new Polygon(true)
                 .add(-SIZE2, 1)
                 .add(SIZE * 3 + SIZE2, 1)

src/main/java/de/neemann/digital/draw/shapes/SplitterShape.java

@@ -55,7 +55,7 @@ public class SplitterShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         for (int i = 0; i < inputs.size(); i++) {
             Vector pos = new Vector(-2, i * SIZE - 3);
             graphic.drawText(pos, pos.add(2, 0), inputs.get(i).getName(), Orientation.RIGHTBOTTOM, Style.SHAPE_PIN);

src/main/java/de/neemann/digital/draw/shapes/SwitchShape.java

@@ -65,7 +65,7 @@ public class SwitchShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         int yOffs = 0;
         if (closed) {
             graphic.drawLine(new Vector(0, 0), new Vector(SIZE * 2, 0), Style.NORMAL);

src/main/java/de/neemann/digital/draw/shapes/TestCaseShape.java

@@ -45,7 +45,7 @@ public class TestCaseShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         Polygon pol = new Polygon(true)
                 .add(SIZE2, SIZE2)
                 .add(SIZE2 + SIZE * 4, SIZE2)

src/main/java/de/neemann/digital/draw/shapes/TextShape.java

@@ -45,7 +45,7 @@ public class TextShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawText(new Vector(0, 0), new Vector(1, 0), label, Orientation.LEFTTOP, Style.NORMAL_TEXT);
     }
 }

src/main/java/de/neemann/digital/draw/shapes/TransGateShape.java

@@ -64,7 +64,7 @@ public class TransGateShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawPolygon(TOP, Style.NORMAL);
         graphic.drawPolygon(BOTTOM, Style.NORMAL);
         graphic.drawLine(new Vector(SIZE, -SIZE), new Vector(SIZE, -SIZE2), Style.NORMAL);

src/main/java/de/neemann/digital/draw/shapes/TunnelShape.java

@@ -48,7 +48,7 @@ public class TunnelShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic gr, boolean highLight) {
+    public void drawTo(Graphic gr, Style highLight) {
         gr.drawPolygon(new Polygon(true)
                 .add(0, 0)
                 .add(WIDTH, HEIGHT)

src/main/java/de/neemann/digital/draw/shapes/VDDShape.java

@@ -45,7 +45,7 @@ public class VDDShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean heighLight) {
+    public void drawTo(Graphic graphic, Style heighLight) {
         graphic.drawPolygon(
                 new Polygon(false)
                         .add(-SIZE2, DOWNSHIFT)

src/main/java/de/neemann/digital/draw/shapes/ieee/IEEEGenericShape.java

@@ -54,7 +54,7 @@ public abstract class IEEEGenericShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         int offs = (inputs.size() / 2 - 1) * SIZE;
         drawIEEE(new GraphicTransform(graphic, v -> v.add(0, offs)));
 

src/main/java/de/neemann/digital/draw/shapes/ieee/IEEENotShape.java

@@ -52,7 +52,7 @@ public class IEEENotShape implements Shape {
     }
 
     @Override
-    public void drawTo(Graphic graphic, boolean highLight) {
+    public void drawTo(Graphic graphic, Style highLight) {
         graphic.drawPolygon(
                 new Polygon(true)
                         .add(1, -SIZE2 - 2)

src/main/java/de/neemann/digital/gui/Main.java

@@ -917,6 +917,11 @@ public final class Main extends JFrame implements ClosingWindowListener.ConfirmS
                 if (createAndStartModel(false, ModelEvent.MICROSTEP, null))
                     circuitComponent.setManualChangeObserver(new MicroStepObserver(model));
             }
+
+            @Override
+            public void leave() {
+                circuitComponent.removeHighLighted();
+            }
         });
     }
 
@@ -1009,6 +1014,7 @@ public final class Main extends JFrame implements ClosingWindowListener.ConfirmS
                 BurnException e = (BurnException) cause;
                 circuitComponent.addHighLightedWires(e.getValues());
             }
+            circuitComponent.setHighLightStyle(Style.ERROR);
             circuitComponent.repaintNeeded();
             new ErrorMessage(message).addCause(cause).show(Main.this);
             stoppedState.enter();

src/main/java/de/neemann/digital/gui/components/CircuitComponent.java

@@ -107,6 +107,7 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
     private ArrayList<Modification> modifications;
     private Circuit initialCircuit;
     private int undoPosition;
+    private Style highLightStyle = Style.HIGHLIGHT;
 
 
     /**
@@ -558,8 +559,19 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
      */
     public void removeHighLighted() {
         highLighted.clear();
+        highLightStyle = Style.HIGHLIGHT;
     }
 
+    /**
+     * Sets the style used to highlight components
+     *
+     * @param highLightStyle the style to highlight components
+     */
+    public void setHighLightStyle(Style highLightStyle) {
+        this.highLightStyle = highLightStyle;
+    }
+
+
     /**
      * Adds the given element to insert to the circuit
      *
@@ -624,7 +636,7 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
             GraphicSwing gr = new GraphicSwing(gr2, (int) (2 / transform.getScaleX()));
 
             long time = System.currentTimeMillis();
-            circuit.drawTo(gr, highLighted, modelSync);
+            circuit.drawTo(gr, highLighted, highLightStyle, modelSync);
             time = System.currentTimeMillis() - time;
 
             if (time > 500) antiAlias = false;
@@ -1137,7 +1149,7 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
         @Override
         public void drawTo(Graphic gr) {
             if (delta != null)
-                element.drawTo(gr, true);
+                element.drawTo(gr, Style.HIGHLIGHT);
         }
 
         @Override
@@ -1203,7 +1215,7 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
 
         @Override
         public void drawTo(Graphic gr) {
-            visualElement.drawTo(gr, true);
+            visualElement.drawTo(gr, Style.HIGHLIGHT);
         }
 
         @Override
@@ -1293,7 +1305,7 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
         @Override
         public void drawTo(Graphic gr) {
             // ensure that highlighted wire is visible by drawing it on top of other drawings.
-            wire.drawTo(gr, true);
+            wire.drawTo(gr, Style.HIGHLIGHT);
         }
 
         @Override
@@ -1350,7 +1362,7 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
 
         @Override
         public void drawTo(Graphic gr) {
-            wire.drawTo(gr, true);
+            wire.drawTo(gr, Style.HIGHLIGHT);
         }
 
         @Override
@@ -1376,7 +1388,7 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
         }
 
         private void activate(Vector startPos) {
-            startPos=raster(startPos);
+            startPos = raster(startPos);
             activate(startPos, startPos);
             selectionMade = false;
         }
@@ -1387,7 +1399,7 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
             wire1 = new Wire(startPos, endPos);
             wire2 = new Wire(startPos, endPos);
             selectionMade = true;
-            lastPosition=endPos;
+            lastPosition = endPos;
             setWires();
         }
 
@@ -1447,8 +1459,8 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
 
         @Override
         public void drawTo(Graphic gr) {
-            wire1.drawTo(gr, true);
+            wire1.drawTo(gr, Style.HIGHLIGHT);
-            wire2.drawTo(gr, true);
+            wire2.drawTo(gr, Style.HIGHLIGHT);
         }
 
         @Override
@@ -1684,7 +1696,7 @@ public class CircuitComponent extends JComponent implements Circuit.ChangedListe
             if (elements != null)
                 for (Movable m : elements)
                     if (m instanceof Drawable)
-                        ((Drawable) m).drawTo(gr, true);
+                        ((Drawable) m).drawTo(gr, Style.HIGHLIGHT);
         }
 
         @Override

src/main/java/de/neemann/digital/gui/components/data/DataSet.java

@@ -140,7 +140,7 @@ public class DataSet implements Iterable<DataSample>, Drawable {
 
 
     @Override
-    synchronized public void drawTo(Graphic g, boolean highLight) {
+    synchronized public void drawTo(Graphic g, Style highLight) {
         int x = getTextBorder();
 
         int yOffs = SIZE / 2;

src/main/java/de/neemann/digital/gui/components/data/DataSetComponent.java

@@ -29,7 +29,7 @@ public class DataSetComponent extends JComponent {
         g.setColor(Color.WHITE);
         g.fillRect(0, 0, getWidth(), getHeight());
 
-        dataSet.drawTo(new GraphicSwing(g2), false);
+        dataSet.drawTo(new GraphicSwing(g2), null);
     }
 
     @Override

src/test/java/de/neemann/digital/docu/DocuTest.java

@@ -117,10 +117,10 @@ public class DocuTest extends TestCase {
 
     private void writeSVG(File imageFile, VisualElement ve) throws IOException {
         GraphicMinMax minMax = new GraphicMinMax(true);
-        ve.drawTo(minMax, false);
+        ve.drawTo(minMax, null);
         try (FileOutputStream out = new FileOutputStream(imageFile)) {
             try (GraphicSVG svg = new GraphicSVG(out, minMax.getMin(), minMax.getMax(), null, 20)) {
-                ve.drawTo(svg, false);
+                ve.drawTo(svg, null);
             }
         }
     }