Removing the prototype on an attribute results in an error

[pascalrobert]

Selecting "No Prototype" on an attribute that already have a prototype results with:

java.lang.RuntimeException: Failed to set value with method public void org.objectstyle.wolips.eomodeler.core.model.EOAttribute.setPrototype(org.objectstyle.wolips.eomodeler.core.model.EOAttribute) on [EOAttribute: newAttribute4].
at org.objectstyle.wolips.eomodeler.core.kvc.MethodKey.setValue(MethodKey.java:77)
at org.objectstyle.wolips.eomodeler.core.kvc.Key.setValue(Key.java:109)
at org.objectstyle.wolips.eomodeler.core.kvc.KeyPath.setValue(KeyPath.java:123)
at org.objectstyle.wolips.eomodeler.utils.ComboViewerBinding.selectionChanged(ComboViewerBinding.java:144)
at org.eclipse.jface.viewers.Viewer$2.run(Viewer.java:164)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:49)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175)
at org.eclipse.jface.viewers.Viewer.fireSelectionChanged(Viewer.java:162)
at org.eclipse.jface.viewers.StructuredViewer.updateSelection(StructuredViewer.java:2188)
at org.eclipse.jface.viewers.StructuredViewer.handleSelect(StructuredViewer.java:1211)
at org.eclipse.jface.viewers.StructuredViewer$4.widgetSelected(StructuredViewer.java:1241)
at org.eclipse.jface.util.OpenStrategy.fireSelectionEvent(OpenStrategy.java:239)
at org.eclipse.jface.util.OpenStrategy.access$4(OpenStrategy.java:233)
at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:403)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4128)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1457)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1480)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1465)
at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1270)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3974)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3613)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2696)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2660)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2494)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:674)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:667)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.objectstyle.wolips.eomodeler.core.kvc.MethodKey.setValue(MethodKey.java:75)
... 42 more
Caused by: java.lang.RuntimeException: Failed to get value from method public abstract java.lang.String org.objectstyle.wolips.eomodeler.core.model.EOModelObject.getName() on null.
at org.objectstyle.wolips.eomodeler.core.kvc.MethodKey.getValue(MethodKey.java:69)
at org.objectstyle.wolips.eomodeler.core.kvc.Key.getValue(Key.java:114)
at org.objectstyle.wolips.eomodeler.core.model.EOAttribute.setPrototype(EOAttribute.java:367)
at org.objectstyle.wolips.eomodeler.core.model.EOAttribute.setPrototype(EOAttribute.java:336)
... 47 more
Caused by: java.lang.NullPointerException
at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.objectstyle.wolips.eomodeler.core.kvc.MethodKey.getValue(MethodKey.java:67)
... 50 more