Persistency service does not return dummy projects anymore.

Seems reasonable but let's see if somebody relies on this somewhere...
refs 2553

org.fortiss.tooling.kernel/trunk/src/org/fortiss/tooling/kernel/internal/PersistencyService.java

@@ -32,7 +32,9 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
+import org.conqat.lib.commons.collections.CollectionUtils;
 import org.conqat.lib.commons.collections.UnmodifiableList;
 import org.eclipse.core.resources.WorkspaceJob;
 import org.eclipse.core.runtime.CoreException;
@@ -63,7 +65,7 @@ import org.osgi.framework.Bundle;
  * @author hoelzl
  * @author $Author$
  * @version $Rev$
- * @ConQAT.Rating YELLOW Hash: 8DEBAB54DBCCDEFE11E26C58CE999DB0
+ * @ConQAT.Rating YELLOW Hash: 23E60A2C8958B99893C8108307551BBE
  */
 public class PersistencyService implements IPersistencyService, IIntrospectiveKernelService {
 
@@ -120,7 +122,9 @@ public class PersistencyService implements IPersistencyService, IIntrospectiveKe
 					.filter(t -> t.getRootModelElement() == activeRootElement)
 					.collect(Collectors.toList()));
 		}
-		return asUnmodifiable(elementCache);
+		Stream<ITopLevelElement> noDummy =
+				elementCache.stream().filter(elt -> !(elt instanceof DummyTopLevelElement));
+		return CollectionUtils.asUnmodifiable(noDummy.collect(Collectors.toList()));
 	}
 
 	/** {@inheritDoc} */