remove default values in abstract style, because
-styles were not working correctly
-we can set null but it is not preserved by (de-)serialization
-basic problem is that EMF allows setting null, but does simple not save it
diff --git a/plugins/org.eclipse.graphiti.mm/model/graphiti.ecore b/plugins/org.eclipse.graphiti.mm/model/graphiti.ecore
index 8df2d19..c3ac7ac 100644
--- a/plugins/org.eclipse.graphiti.mm/model/graphiti.ecore
+++ b/plugins/org.eclipse.graphiti.mm/model/graphiti.ecore
@@ -234,10 +234,9 @@
         <eStructuralFeatures xsi:type="ecore:EReference" name="foreground" ordered="false"
             unique="false" eType="#//algorithms/styles/Color"/>
         <eStructuralFeatures xsi:type="ecore:EAttribute" name="lineWidth" ordered="false"
-            unique="false" eType="ecore:EDataType http://www.eclipse.org/emf/2002/Ecore#//EIntegerObject"
-            defaultValueLiteral="1"/>
+            unique="false" eType="ecore:EDataType http://www.eclipse.org/emf/2002/Ecore#//EIntegerObject"/>
         <eStructuralFeatures xsi:type="ecore:EAttribute" name="lineStyle" ordered="false"
-            unique="false" eType="#//algorithms/styles/LineStyle" defaultValueLiteral="SOLID"/>
+            unique="false" eType="#//algorithms/styles/LineStyle"/>
         <eStructuralFeatures xsi:type="ecore:EAttribute" name="filled" ordered="false"
             unique="false" eType="ecore:EDataType http://www.eclipse.org/emf/2002/Ecore#//EBooleanObject"
             defaultValueLiteral="true"/>
@@ -247,8 +246,7 @@
         <eStructuralFeatures xsi:type="ecore:EReference" name="renderingStyle" ordered="false"
             unique="false" eType="#//algorithms/styles/RenderingStyle" containment="true"/>
         <eStructuralFeatures xsi:type="ecore:EAttribute" name="transparency" ordered="false"
-            unique="false" eType="ecore:EDataType http://www.eclipse.org/emf/2002/Ecore#//EDoubleObject"
-            defaultValueLiteral="0"/>
+            unique="false" eType="ecore:EDataType http://www.eclipse.org/emf/2002/Ecore#//EDoubleObject"/>
       </eClassifiers>
       <eClassifiers xsi:type="ecore:EClass" name="GradientColoredLocation">
         <eStructuralFeatures xsi:type="ecore:EAttribute" name="locationType" lowerBound="1"
diff --git a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/impl/GraphicsAlgorithmImpl.java b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/impl/GraphicsAlgorithmImpl.java
index b473b59..c954c2d 100644
--- a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/impl/GraphicsAlgorithmImpl.java
+++ b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/impl/GraphicsAlgorithmImpl.java
@@ -102,7 +102,7 @@
 	 * @generated
 	 * @ordered
 	 */
-	protected static final Integer LINE_WIDTH_EDEFAULT = new Integer(1);
+	protected static final Integer LINE_WIDTH_EDEFAULT = null;
 
 	/**
 	 * The cached value of the '{@link #getLineWidth() <em>Line Width</em>}' attribute.
@@ -192,7 +192,7 @@
 	 * @generated
 	 * @ordered
 	 */
-	protected static final Double TRANSPARENCY_EDEFAULT = new Double(0.0);
+	protected static final Double TRANSPARENCY_EDEFAULT = null;
 
 	/**
 	 * The cached value of the '{@link #getTransparency() <em>Transparency</em>}' attribute.
diff --git a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/AbstractStyle.java b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/AbstractStyle.java
index bf430d7..6a39ab5 100644
--- a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/AbstractStyle.java
+++ b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/AbstractStyle.java
@@ -94,7 +94,6 @@
 
 	/**
 	 * Returns the value of the '<em><b>Line Width</b></em>' attribute.
-	 * The default value is <code>"1"</code>.
 	 * <!-- begin-user-doc -->
 	 * <p>
 	 * If the meaning of the '<em>Line Width</em>' attribute isn't clear,
@@ -104,7 +103,7 @@
 	 * @return the value of the '<em>Line Width</em>' attribute.
 	 * @see #setLineWidth(Integer)
 	 * @see org.eclipse.graphiti.mm.algorithms.styles.StylesPackage#getAbstractStyle_LineWidth()
-	 * @model default="1" unique="false" ordered="false"
+	 * @model unique="false" ordered="false"
 	 * @generated
 	 */
 	Integer getLineWidth();
@@ -121,7 +120,6 @@
 
 	/**
 	 * Returns the value of the '<em><b>Line Style</b></em>' attribute.
-	 * The default value is <code>"SOLID"</code>.
 	 * The literals are from the enumeration {@link org.eclipse.graphiti.mm.algorithms.styles.LineStyle}.
 	 * <!-- begin-user-doc -->
 	 * <p>
@@ -133,7 +131,7 @@
 	 * @see org.eclipse.graphiti.mm.algorithms.styles.LineStyle
 	 * @see #setLineStyle(LineStyle)
 	 * @see org.eclipse.graphiti.mm.algorithms.styles.StylesPackage#getAbstractStyle_LineStyle()
-	 * @model default="SOLID" unique="false" ordered="false"
+	 * @model unique="false" ordered="false"
 	 * @generated
 	 */
 	LineStyle getLineStyle();
@@ -231,7 +229,6 @@
 
 	/**
 	 * Returns the value of the '<em><b>Transparency</b></em>' attribute.
-	 * The default value is <code>"0"</code>.
 	 * <!-- begin-user-doc -->
 	 * <p>
 	 * If the meaning of the '<em>Transparency</em>' attribute isn't clear,
@@ -241,7 +238,7 @@
 	 * @return the value of the '<em>Transparency</em>' attribute.
 	 * @see #setTransparency(Double)
 	 * @see org.eclipse.graphiti.mm.algorithms.styles.StylesPackage#getAbstractStyle_Transparency()
-	 * @model default="0" unique="false" ordered="false"
+	 * @model unique="false" ordered="false"
 	 * @generated
 	 */
 	Double getTransparency();
diff --git a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/AbstractStyleImpl.java b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/AbstractStyleImpl.java
index 5b76834..8d7bece 100644
--- a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/AbstractStyleImpl.java
+++ b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/AbstractStyleImpl.java
@@ -78,7 +78,7 @@
 	 * @generated
 	 * @ordered
 	 */
-	protected static final Integer LINE_WIDTH_EDEFAULT = new Integer(1);
+	protected static final Integer LINE_WIDTH_EDEFAULT = null;
 
 	/**
 	 * The cached value of the '{@link #getLineWidth() <em>Line Width</em>}' attribute.
@@ -168,7 +168,7 @@
 	 * @generated
 	 * @ordered
 	 */
-	protected static final Double TRANSPARENCY_EDEFAULT = new Double(0.0);
+	protected static final Double TRANSPARENCY_EDEFAULT = null;
 
 	/**
 	 * The cached value of the '{@link #getTransparency() <em>Transparency</em>}' attribute.
diff --git a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/StyleImpl.java b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/StyleImpl.java
index 3600b8f..25e37d2 100644
--- a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/StyleImpl.java
+++ b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/StyleImpl.java
@@ -97,7 +97,7 @@
 	 * @generated
 	 * @ordered
 	 */
-	protected static final Integer LINE_WIDTH_EDEFAULT = new Integer(1);
+	protected static final Integer LINE_WIDTH_EDEFAULT = null;
 
 	/**
 	 * The cached value of the '{@link #getLineWidth() <em>Line Width</em>}' attribute.
@@ -187,7 +187,7 @@
 	 * @generated
 	 * @ordered
 	 */
-	protected static final Double TRANSPARENCY_EDEFAULT = new Double(0.0);
+	protected static final Double TRANSPARENCY_EDEFAULT = null;
 
 	/**
 	 * The cached value of the '{@link #getTransparency() <em>Transparency</em>}' attribute.
diff --git a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/StylesPackageImpl.java b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/StylesPackageImpl.java
index 190cfa8..8e43409 100644
--- a/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/StylesPackageImpl.java
+++ b/plugins/org.eclipse.graphiti.mm/src-gen/org/eclipse/graphiti/mm/algorithms/styles/impl/StylesPackageImpl.java
@@ -844,12 +844,12 @@
 		initEClass(abstractStyleEClass, AbstractStyle.class, "AbstractStyle", IS_ABSTRACT, !IS_INTERFACE, IS_GENERATED_INSTANCE_CLASS);
 		initEReference(getAbstractStyle_Background(), this.getColor(), null, "background", null, 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_COMPOSITE, IS_RESOLVE_PROXIES, !IS_UNSETTABLE, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
 		initEReference(getAbstractStyle_Foreground(), this.getColor(), null, "foreground", null, 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_COMPOSITE, IS_RESOLVE_PROXIES, !IS_UNSETTABLE, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
-		initEAttribute(getAbstractStyle_LineWidth(), ecorePackage.getEIntegerObject(), "lineWidth", "1", 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_UNSETTABLE, !IS_ID, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
-		initEAttribute(getAbstractStyle_LineStyle(), this.getLineStyle(), "lineStyle", "SOLID", 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_UNSETTABLE, !IS_ID, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
+		initEAttribute(getAbstractStyle_LineWidth(), ecorePackage.getEIntegerObject(), "lineWidth", null, 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_UNSETTABLE, !IS_ID, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
+		initEAttribute(getAbstractStyle_LineStyle(), this.getLineStyle(), "lineStyle", null, 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_UNSETTABLE, !IS_ID, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
 		initEAttribute(getAbstractStyle_Filled(), ecorePackage.getEBooleanObject(), "filled", "true", 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_UNSETTABLE, !IS_ID, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
 		initEAttribute(getAbstractStyle_LineVisible(), ecorePackage.getEBooleanObject(), "lineVisible", "true", 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_UNSETTABLE, !IS_ID, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
 		initEReference(getAbstractStyle_RenderingStyle(), this.getRenderingStyle(), null, "renderingStyle", null, 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, IS_COMPOSITE, IS_RESOLVE_PROXIES, !IS_UNSETTABLE, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
-		initEAttribute(getAbstractStyle_Transparency(), ecorePackage.getEDoubleObject(), "transparency", "0", 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_UNSETTABLE, !IS_ID, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
+		initEAttribute(getAbstractStyle_Transparency(), ecorePackage.getEDoubleObject(), "transparency", null, 0, 1, AbstractStyle.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_UNSETTABLE, !IS_ID, !IS_UNIQUE, !IS_DERIVED, !IS_ORDERED);
 
 		initEClass(gradientColoredLocationEClass, GradientColoredLocation.class, "GradientColoredLocation", !IS_ABSTRACT, !IS_INTERFACE, IS_GENERATED_INSTANCE_CLASS);
 		initEAttribute(getGradientColoredLocation_LocationType(), this.getLocationType(), "locationType", null, 1, 1, GradientColoredLocation.class, !IS_TRANSIENT, !IS_VOLATILE, IS_CHANGEABLE, !IS_UNSETTABLE, !IS_ID, IS_UNIQUE, !IS_DERIVED, IS_ORDERED);