Added some null checks


diff --git a/plugins/org.eclipse.etrice.ui.common.base/src/org/eclipse/etrice/ui/common/base/dialogs/AbstractPropertyDialog.java b/plugins/org.eclipse.etrice.ui.common.base/src/org/eclipse/etrice/ui/common/base/dialogs/AbstractPropertyDialog.java
index b848266..912f9f3 100644
--- a/plugins/org.eclipse.etrice.ui.common.base/src/org/eclipse/etrice/ui/common/base/dialogs/AbstractPropertyDialog.java
+++ b/plugins/org.eclipse.etrice.ui.common.base/src/org/eclipse/etrice/ui/common/base/dialogs/AbstractPropertyDialog.java
@@ -205,6 +205,9 @@
 		
 		@Override
 		public Object convert(Object fromObject) {
+			if (fromObject==null)
+				return "";
+			
 			return ((Enumerator)fromObject).getLiteral();
 		}
 	}
diff --git a/plugins/org.eclipse.etrice.ui.common.base/src/org/eclipse/etrice/ui/common/base/support/ChangeAwareCreateConnectionFeature.java b/plugins/org.eclipse.etrice.ui.common.base/src/org/eclipse/etrice/ui/common/base/support/ChangeAwareCreateConnectionFeature.java
index e7b4e0e..f328a99 100644
--- a/plugins/org.eclipse.etrice.ui.common.base/src/org/eclipse/etrice/ui/common/base/support/ChangeAwareCreateConnectionFeature.java
+++ b/plugins/org.eclipse.etrice.ui.common.base/src/org/eclipse/etrice/ui/common/base/support/ChangeAwareCreateConnectionFeature.java
@@ -45,6 +45,9 @@
 
 	@Override
 	public final boolean hasDoneChanges() {
+		if (changeRecorder==null)
+			return false;
+		
 		return changeRecorder.hasResourceChanged();
 	}