diff --git a/com.archimatetool.editor/src/com/archimatetool/editor/diagram/actions/TextAlignmentAction.java b/com.archimatetool.editor/src/com/archimatetool/editor/diagram/actions/TextAlignmentAction.java
index 0b8f577f5..1065d8575 100644
--- a/com.archimatetool.editor/src/com/archimatetool/editor/diagram/actions/TextAlignmentAction.java
+++ b/com.archimatetool.editor/src/com/archimatetool/editor/diagram/actions/TextAlignmentAction.java
@@ -17,7 +17,7 @@
 import org.eclipse.ui.actions.RetargetAction;
 
 import com.archimatetool.editor.diagram.commands.TextAlignmentCommand;
-import com.archimatetool.editor.ui.factory.IObjectUIProvider;
+import com.archimatetool.editor.ui.factory.IGraphicalObjectUIProvider;
 import com.archimatetool.editor.ui.factory.ObjectUIFactory;
 import com.archimatetool.model.IArchimatePackage;
 import com.archimatetool.model.ILockable;
@@ -117,7 +117,7 @@ private List<ITextAlignment> getValidSelectedObjects() {
         for(Object object : getSelectedObjects()) {
             if(object instanceof EditPart editPart && editPart.getModel() instanceof ITextAlignment textAlignmentObject
                     && !(textAlignmentObject instanceof ILockable lockable && lockable.isLocked())
-                    && ObjectUIFactory.INSTANCE.getProvider(textAlignmentObject) instanceof IObjectUIProvider provider
+                    && ObjectUIFactory.INSTANCE.getProvider(textAlignmentObject) instanceof IGraphicalObjectUIProvider provider
                     && provider.shouldExposeFeature(IArchimatePackage.Literals.TEXT_ALIGNMENT__TEXT_ALIGNMENT.getName())) {
                 list.add(textAlignmentObject);
             }
diff --git a/com.archimatetool.editor/src/com/archimatetool/editor/diagram/actions/TextPositionAction.java b/com.archimatetool.editor/src/com/archimatetool/editor/diagram/actions/TextPositionAction.java
index 00b6e4b42..fa74eced6 100644
--- a/com.archimatetool.editor/src/com/archimatetool/editor/diagram/actions/TextPositionAction.java
+++ b/com.archimatetool.editor/src/com/archimatetool/editor/diagram/actions/TextPositionAction.java
@@ -17,7 +17,7 @@
 import org.eclipse.ui.actions.RetargetAction;
 
 import com.archimatetool.editor.diagram.commands.TextPositionCommand;
-import com.archimatetool.editor.ui.factory.IObjectUIProvider;
+import com.archimatetool.editor.ui.factory.IGraphicalObjectUIProvider;
 import com.archimatetool.editor.ui.factory.ObjectUIFactory;
 import com.archimatetool.model.IArchimatePackage;
 import com.archimatetool.model.ILockable;
@@ -117,7 +117,7 @@ private List<ITextPosition> getValidSelectedObjects() {
         for(Object object : getSelectedObjects()) {
             if(object instanceof EditPart editPart && editPart.getModel() instanceof ITextPosition textPositionObject
                     && !(textPositionObject instanceof ILockable lockable && lockable.isLocked())
-                    && ObjectUIFactory.INSTANCE.getProvider(textPositionObject) instanceof IObjectUIProvider provider
+                    && ObjectUIFactory.INSTANCE.getProvider(textPositionObject) instanceof IGraphicalObjectUIProvider provider
                     && provider.shouldExposeFeature(IArchimatePackage.Literals.TEXT_POSITION__TEXT_POSITION.getName())) {
                 list.add(textPositionObject);
             }
diff --git a/com.archimatetool.editor/src/com/archimatetool/editor/views/tree/TreeSelectionSynchroniser.java b/com.archimatetool.editor/src/com/archimatetool/editor/views/tree/TreeSelectionSynchroniser.java
index 5ecc3e5d6..a881ba4ca 100644
--- a/com.archimatetool.editor/src/com/archimatetool/editor/views/tree/TreeSelectionSynchroniser.java
+++ b/com.archimatetool.editor/src/com/archimatetool/editor/views/tree/TreeSelectionSynchroniser.java
@@ -124,14 +124,14 @@ private boolean doSync() {
     }
     
     /**
-     * Update with the last known selection
+     * Update with the last known selections
      */
     private void updateSelection() {
         // In this case we have created a new TreeViewer and synchroniser, so create a new selection event
         if(lastSelectionEvent == null) {
             IEditorPart activeEditor = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().getActiveEditor();
-            if(activeEditor instanceof IDiagramModelEditor editor && editor.getGraphicalViewer() instanceof GraphicalViewer viewer) { // check this is not a zombie editor part
-                selectionChanged(new SelectionChangedEvent(viewer, viewer.getSelection()));
+            if(activeEditor instanceof IDiagramModelEditor editor && editor.getGraphicalViewer() != null) { // check this is not a zombie editor part
+                selectionChanged(new SelectionChangedEvent(editor.getGraphicalViewer(), editor.getGraphicalViewer().getSelection()));
             }
         }
         else {