1) I created a simple 2-table relational model, created a FK between two tables

2) Save ALL

3) Select both tables in the Diagram and hit "DELETE" key

get:
ava.lang.IllegalArgumentException: modelResource is null
at com.metamatrix.core.util.CoreArgCheck.isNotNull(CoreArgCheck.java:139)
at org.teiid.designer.core.extension.EmfModelObjectExtensionAssistant.getModelResource(EmfModelObjectExtensionAssistant.java:61)
at org.teiid.designer.core.extension.EmfModelObjectExtensionAssistant.getSupportedNamespaces(EmfModelObjectExtensionAssistant.java:237)
at org.teiid.designer.extension.ModelExtensionAssistantAggregator.getSupportedNamespacePrefixes(ModelExtensionAssistantAggregator.java:104)
at org.teiid.designer.extension.ModelExtensionAssistantAggregator.getPropertyDefinitions(ModelExtensionAssistantAggregator.java:62)
at org.teiid.designer.ui.properties.extension.ModelExtensionPropertySource.getPropertyDescriptors(ModelExtensionPropertySource.java:65)
at com.metamatrix.modeler.internal.ui.properties.ModelObjectPropertySource.getAllDescriptors(ModelObjectPropertySource.java:211)
at com.metamatrix.modeler.internal.ui.properties.ModelObjectPropertySource.getPropertyDescriptors(ModelObjectPropertySource.java:309)
at org.eclipse.ui.views.properties.PropertySheetEntry.computeMergedPropertyDescriptors(PropertySheetEntry.java:167)
at org.eclipse.ui.views.properties.PropertySheetEntry.refreshChildEntries(PropertySheetEntry.java:530)
at org.eclipse.ui.views.properties.PropertySheetEntry.setValues(PropertySheetEntry.java:760)
at org.eclipse.ui.views.properties.PropertySheetViewer.setInput(PropertySheetViewer.java:973)
at org.eclipse.ui.views.properties.PropertySheetPage.selectionChanged(PropertySheetPage.java:510)
at com.metamatrix.modeler.internal.ui.properties.ModelObjectPropertySheetPage.selectionChanged(ModelObjectPropertySheetPage.java:102)
at org.eclipse.ui.views.properties.PropertySheet.selectionChanged(PropertySheet.java:363)
at org.eclipse.ui.internal.AbstractSelectionService.firePostSelection(AbstractSelectionService.java:179)
at org.eclipse.ui.internal.AbstractSelectionService$2.selectionChanged(AbstractSelectionService.java:71)
at com.metamatrix.modeler.internal.ui.editors.ModelEditorSelectionProvider$2.run(ModelEditorSelectionProvider.java:145)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at com.metamatrix.modeler.internal.ui.editors.ModelEditorSelectionProvider.fireSelectionChanged(ModelEditorSelectionProvider.java:143)
at com.metamatrix.modeler.internal.ui.editors.ModelEditorSelectionProvider.setSelection(ModelEditorSelectionProvider.java:121)
at com.metamatrix.modeler.internal.ui.editors.ModelEditorSelectionProvider$1.selectionChanged(ModelEditorSelectionProvider.java:43)
at com.metamatrix.modeler.diagram.ui.editor.DiagramEditorSelectionProvider.fireSelectionChanged(DiagramEditorSelectionProvider.java:88)
at com.metamatrix.modeler.diagram.ui.editor.DiagramEditorSelectionProvider.selectionChanged(DiagramEditorSelectionProvider.java:83)
at org.eclipse.gef.ui.parts.AbstractEditPartViewer.fireSelectionChanged(AbstractEditPartViewer.java:247)
at org.eclipse.gef.ui.parts.AbstractEditPartViewer$1.run(AbstractEditPartViewer.java:131)
at org.eclipse.gef.SelectionManager.fireSelectionChanged(SelectionManager.java:144)
at org.eclipse.gef.SelectionManager.deselect(SelectionManager.java:118)
at org.eclipse.gef.ui.parts.AbstractEditPartViewer.deselect(AbstractEditPartViewer.java:202)
at org.eclipse.gef.editparts.AbstractEditPart.removeNotify(AbstractEditPart.java:942)
at org.eclipse.gef.editparts.AbstractGraphicalEditPart.removeNotify(AbstractGraphicalEditPart.java:823)
at org.eclipse.gef.editparts.AbstractEditPart.removeChild(AbstractEditPart.java:880)
at org.eclipse.gef.editparts.AbstractEditPart.refreshChildren(AbstractEditPart.java:793)
at com.metamatrix.modeler.diagram.ui.pakkage.PackageDiagramEditPart.propertyChange(PackageDiagramEditPart.java:193)
at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
at com.metamatrix.modeler.diagram.ui.model.AbstractLocalDiagramModelNode.fireStructureChange(AbstractLocalDiagramModelNode.java:296)
at com.metamatrix.modeler.diagram.ui.model.AbstractLocalDiagramModelNode.removeChild(AbstractLocalDiagramModelNode.java:151)
at com.metamatrix.modeler.diagram.ui.pakkage.PackageDiagramModelFactory.performRemove(PackageDiagramModelFactory.java:688)
at com.metamatrix.modeler.diagram.ui.pakkage.PackageDiagramModelFactory.handleSingleNotification(PackageDiagramModelFactory.java:507)
at com.metamatrix.modeler.diagram.ui.pakkage.PackageDiagramModelFactory.handleNotification(PackageDiagramModelFactory.java:492)
at com.metamatrix.modeler.diagram.ui.pakkage.PackageDiagramModelFactory.notifyModel(PackageDiagramModelFactory.java:336)
at com.metamatrix.modeler.diagram.ui.editor.DiagramEditor.notifyChanged(DiagramEditor.java:1063)
at com.metamatrix.modeler.internal.ui.editors.ModelEditor$5.run(ModelEditor.java:1132)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3563)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3212)
at org.eclipse.jface.operation.ModalContext$ModalContextThread.block(ModalContext.java:173)
at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:388)
at org.eclipse.jface.dialogs.ProgressMonitorDialog.run(ProgressMonitorDialog.java:507)
at com.metamatrix.modeler.internal.ui.actions.workers.DeleteWorker.executeCommand(DeleteWorker.java:221)
at com.metamatrix.modeler.internal.ui.actions.workers.DeleteWorker.execute(DeleteWorker.java:132)
at com.metamatrix.modeler.internal.ui.actions.ModelObjectAction.doRun(ModelObjectAction.java:60)
at com.metamatrix.modeler.internal.ui.actions.DeleteAction.doRun(DeleteAction.java:91)