diff --git a/de.prob.standalone/plugin.xml b/de.prob.standalone/plugin.xml
index 5011fc7bd78081d08fc601b0dfbd99c1858390ae..97e9f1d8f3f097e9e36568935664efcbcdd16217 100644
--- a/de.prob.standalone/plugin.xml
+++ b/de.prob.standalone/plugin.xml
@@ -70,11 +70,18 @@
                         <instanceof
                               value="org.eclipse.core.resources.IResource">
                         </instanceof>
-                        <test
-                              forcePluginActivation="true"
-                              property="org.eclipse.core.resources.extension"
-                              value="mch">
-                        </test>
+                        <or>
+                           <test
+                                 forcePluginActivation="true"
+                                 property="org.eclipse.core.resources.extension"
+                                 value="mch">
+                           </test>
+                           <test
+                                 forcePluginActivation="true"
+                                 property="org.eclipse.core.resources.extension"
+                                 value="ref">
+                           </test>
+                        </or>
                      </and>
                   </iterate>
                </with>
@@ -323,117 +330,54 @@
         point="org.eclipse.ui.navigator.navigatorContent">
      <navigatorContent
            activeByDefault="true"
-           contentProvider="de.prob.standalone.internal.FormalModelContentProvider"
-           id="de.prob.standalone.navigatorContent.formalModelContent"
-           labelProvider="de.prob.standalone.internal.FormalModelLabelProvider"
-           name="Formal Model Content"
+           contentProvider="de.prob.standalone.internal.ProBNavigatorContentProvider"
+           id="de.prob.standalone.navigatorContent.probContent"
+           labelProvider="de.prob.standalone.internal.ProBNavigatorLabelProvider"
+           name="ProB Navigation Content Provider"
            priority="normal">
         <triggerPoints>
-           <or>
-              <and>
-                 <instanceof
-                       value="org.eclipse.core.resources.IResource">
-                 </instanceof>
-                 <test
-                       forcePluginActivation="true"
-                       property="org.eclipse.core.resources.extension"
-                       value="bum">
-                 </test>
-              </and>
-              <and>
-                 <instanceof
-                       value="org.eclipse.core.resources.IResource">
-                 </instanceof>
-                 <test
-                       forcePluginActivation="true"
-                       property="org.eclipse.core.resources.extension"
-                       value="buc">
-                 </test>
-              </and>
-              <and>
-                 <instanceof
-                       value="org.eclipse.core.resources.IResource">
-                 </instanceof>
-                 <test
-                       forcePluginActivation="true"
-                       property="org.eclipse.core.resources.extension"
-                       value="mch">
-                 </test>
-              </and>
-              <and>
-                 <instanceof
-                       value="org.eclipse.core.resources.IResource">
-                 </instanceof>
-                 <test
-                       forcePluginActivation="true"
-                       property="org.eclipse.core.resources.extension"
-                       value="bmso">
-                 </test>
-              </and>
-           </or>
+           <instanceof
+                 value="org.eclipse.core.resources.IResource">
+           </instanceof>
         </triggerPoints>
      </navigatorContent>
      <commonFilter
            activeByDefault="true"
            id="de.prob.standalone.commonFilter.probFileFilter"
-           name="ProB File Filter">
+           name="ProB Navigation Filter">
         <filterExpression>
            <or>
-              <instanceof
-                    value="org.eclipse.core.resources.IFolder">
-              </instanceof>
               <and>
                  <instanceof
-                       value="org.eclipse.core.resources.IFile">
+                       value="org.eclipse.core.resources.IResource">
                  </instanceof>
-                 <not>
-                    <and>
-                       <instanceof
-                             value="org.eclipse.core.resources.IFile">
-                       </instanceof>
-                       <test
-                             forcePluginActivation="true"
-                             property="org.eclipse.core.resources.extension"
-                             value="buc">
-                       </test>
-                    </and>
-                 </not>
-                 <not>
-                    <and>
-                       <instanceof
-                             value="org.eclipse.core.resources.IFile">
-                       </instanceof>
-                       <test
-                             forcePluginActivation="true"
-                             property="org.eclipse.core.resources.extension"
-                             value="bum">
-                       </test>
-                    </and>
-                 </not>
-                 <not>
-                    <and>
-                       <instanceof
-                             value="org.eclipse.core.resources.IFile">
-                       </instanceof>
-                       <test
-                             forcePluginActivation="true"
-                             property="org.eclipse.core.resources.extension"
-                             value="bmso">
-                       </test>
-                    </and>
-                 </not>
-                 <not>
-                    <and>
-                       <instanceof
-                             value="org.eclipse.core.resources.IFile">
-                       </instanceof>
-                       <test
-                             forcePluginActivation="true"
-                             property="org.eclipse.core.resources.extension"
-                             value="mch">
-                       </test>
-                    </and>
-                 </not>
+                 <or>
+                    <test
+                          forcePluginActivation="true"
+                          property="org.eclipse.core.resources.extension"
+                          value="bcc">
+                    </test>
+                    <test
+                          forcePluginActivation="true"
+                          property="org.eclipse.core.resources.extension"
+                          value="bpo">
+                    </test>
+                    <test
+                          forcePluginActivation="true"
+                          property="org.eclipse.core.resources.extension"
+                          value="bpr">
+                    </test>
+                    <test
+                          forcePluginActivation="true"
+                          property="org.eclipse.core.resources.extension"
+                          value="bps">
+                    </test>
+                    <test
+                          forcePluginActivation="true"
+                          property="org.eclipse.core.resources.extension"
+                          value="bcm">
+                    </test>
+                 </or>
               </and>
            </or>
         </filterExpression>
diff --git a/de.prob.standalone/src/de/prob/standalone/internal/FormalModelContentProvider.java b/de.prob.standalone/src/de/prob/standalone/internal/ProBNavigatorContentProvider.java
similarity index 87%
rename from de.prob.standalone/src/de/prob/standalone/internal/FormalModelContentProvider.java
rename to de.prob.standalone/src/de/prob/standalone/internal/ProBNavigatorContentProvider.java
index 027c41ad22447d007135438bad820dfaebe5ddb2..a203bd94a9afd92c93dba38ea32b07911f94e19d 100644
--- a/de.prob.standalone/src/de/prob/standalone/internal/FormalModelContentProvider.java
+++ b/de.prob.standalone/src/de/prob/standalone/internal/ProBNavigatorContentProvider.java
@@ -1,39 +1,39 @@
-package de.prob.standalone.internal;
-
-/** 
- * (c) 2009 Lehrstuhl fuer Softwaretechnik und Programmiersprachen, 
- * Heinrich Heine Universitaet Duesseldorf
- * This software is licenced under EPL 1.0 (http://www.eclipse.org/org/documents/epl-v10.html) 
- * */
-
-import org.eclipse.jface.viewers.ITreeContentProvider;
-import org.eclipse.jface.viewers.Viewer;
-
-public class FormalModelContentProvider implements ITreeContentProvider {
-
-	public Object getParent(final Object element) {
-		return null;
-	}
-
-	public boolean hasChildren(final Object element) {
-		return false;
-	}
-
-	public Object[] getElements(final Object inputElement) {
-		return null;
-	}
-
-	public void dispose() {
-		// do nothing
-	}
-
-	public void inputChanged(final Viewer viewer, final Object oldInput,
-			final Object newInput) {
-		// do nothing
-	}
-
-	public Object[] getChildren(Object parentElement) {
-		return null;
-	}
-
-}
+package de.prob.standalone.internal;
+
+/** 
+ * (c) 2009 Lehrstuhl fuer Softwaretechnik und Programmiersprachen, 
+ * Heinrich Heine Universitaet Duesseldorf
+ * This software is licenced under EPL 1.0 (http://www.eclipse.org/org/documents/epl-v10.html) 
+ * */
+
+import org.eclipse.jface.viewers.ITreeContentProvider;
+import org.eclipse.jface.viewers.Viewer;
+
+public class ProBNavigatorContentProvider implements ITreeContentProvider {
+
+	public Object getParent(final Object element) {
+		return null;
+	}
+
+	public boolean hasChildren(final Object element) {
+		return false;
+	}
+
+	public Object[] getElements(final Object inputElement) {
+		return null;
+	}
+
+	public void dispose() {
+		// do nothing
+	}
+
+	public void inputChanged(final Viewer viewer, final Object oldInput,
+			final Object newInput) {
+		// do nothing
+	}
+
+	public Object[] getChildren(Object parentElement) {
+		return null;
+	}
+
+}
diff --git a/de.prob.standalone/src/de/prob/standalone/internal/FormalModelLabelProvider.java b/de.prob.standalone/src/de/prob/standalone/internal/ProBNavigatorLabelProvider.java
similarity index 90%
rename from de.prob.standalone/src/de/prob/standalone/internal/FormalModelLabelProvider.java
rename to de.prob.standalone/src/de/prob/standalone/internal/ProBNavigatorLabelProvider.java
index f28f7dd05660d6c5238265595957f7e5009f5a64..3b7b6a4a351309819e2e84d00d88d3a1da22dbc5 100644
--- a/de.prob.standalone/src/de/prob/standalone/internal/FormalModelLabelProvider.java
+++ b/de.prob.standalone/src/de/prob/standalone/internal/ProBNavigatorLabelProvider.java
@@ -1,59 +1,60 @@
-package de.prob.standalone.internal;
-
-/** 
- * (c) 2009 Lehrstuhl fuer Softwaretechnik und Programmiersprachen, 
- * Heinrich Heine Universitaet Duesseldorf
- * This software is licenced under EPL 1.0 (http://www.eclipse.org/org/documents/epl-v10.html) 
- * */
-
-import org.eclipse.core.resources.IFile;
-import org.eclipse.jface.viewers.ILabelProvider;
-import org.eclipse.jface.viewers.ILabelProviderListener;
-import org.eclipse.swt.graphics.Image;
-
-import de.prob.standalone.Activator;
-
-public class FormalModelLabelProvider implements ILabelProvider {
-
-	public Image getImage(final Object element) {
-		if (element instanceof IFile) {
-			IFile file = (IFile) element;
-			if (file.getFileExtension().equals("bum")) {
-				return Activator.getImageDescriptor("icons/eventb/mch_obj.png")
-						.createImage();
-			} else if (file.getFileExtension().equals("buc")) {
-				return Activator.getImageDescriptor("icons/eventb/ctx_obj.png")
-						.createImage();
-			} else if (file.getFileExtension().equals("mch")) {
-				return Activator.getImageDescriptor("icons/icon16.png")
-						.createImage();
-			}
-		}
-		return null;
-	}
-
-	public String getText(final Object element) {
-		if (element instanceof IFile) {
-			IFile file = (IFile) element;
-			return file.getName().replace("." + file.getFileExtension(), "");
-		}
-		return null;
-	}
-
-	public void addListener(final ILabelProviderListener listener) {
-		// do nothing
-	}
-
-	public void dispose() {
-		// do nothing
-	}
-
-	public boolean isLabelProperty(final Object element, final String property) {
-		return false;
-	}
-
-	public void removeListener(final ILabelProviderListener listener) {
-		// do nothing
-	}
-
-}
+package de.prob.standalone.internal;
+
+/** 
+ * (c) 2009 Lehrstuhl fuer Softwaretechnik und Programmiersprachen, 
+ * Heinrich Heine Universitaet Duesseldorf
+ * This software is licenced under EPL 1.0 (http://www.eclipse.org/org/documents/epl-v10.html) 
+ * */
+
+import org.eclipse.core.resources.IFile;
+import org.eclipse.jface.viewers.ILabelProvider;
+import org.eclipse.jface.viewers.ILabelProviderListener;
+import org.eclipse.swt.graphics.Image;
+
+import de.prob.standalone.Activator;
+
+public class ProBNavigatorLabelProvider implements ILabelProvider {
+
+	public Image getImage(final Object element) {
+		// TODO: (LL) Needs to be improved
+		if (element instanceof IFile) {
+			IFile file = (IFile) element;
+			if (file.getFileExtension().equals("bum")) {
+				return Activator.getImageDescriptor("icons/eventb/mch_obj.png")
+						.createImage();
+			} else if (file.getFileExtension().equals("buc")) {
+				return Activator.getImageDescriptor("icons/eventb/ctx_obj.png")
+						.createImage();
+			} else if (file.getFileExtension().equals("mch")) {
+				return Activator.getImageDescriptor("icons/icon16.png")
+						.createImage();
+			}
+		}
+		return null;
+	}
+
+	public String getText(final Object element) {
+		if (element instanceof IFile) {
+			IFile file = (IFile) element;
+			return file.getName().replace("." + file.getFileExtension(), "");
+		}
+		return null;
+	}
+
+	public void addListener(final ILabelProviderListener listener) {
+		// do nothing
+	}
+
+	public void dispose() {
+		// do nothing
+	}
+
+	public boolean isLabelProperty(final Object element, final String property) {
+		return false;
+	}
+
+	public void removeListener(final ILabelProviderListener listener) {
+		// do nothing
+	}
+
+}