NullPointerException can be thrown while restoring use cases. Haven't yet narrowed down when it happens.

!STACK 0
java.lang.NullPointerException
at ncsa.analysis.validators.ResultNameValidator$NameDoesNotExistValidator.checkIsValid(ResultNameValidator.java:43)
at ncsa.analysis.types.ParameterNodeValidator.isValid(ParameterNodeValidator.java:36)
at ncsa.analysis.validators.CombinationValidator.checkIsValid(CombinationValidator.java:44)
at ncsa.analysis.types.ParameterNodeValidator.isValid(ParameterNodeValidator.java:36)
at ncsa.analysis.types.ParameterNode.isValid(ParameterNode.java:97)
at ncsa.analysis.types.ParameterNode.setActualValue(ParameterNode.java:139)
at ncsa.analysis.types.ParameterNode.setValueFromSerializedElement(ParameterNode.java:117)
at ncsa.analysis.types.UseCase.populateNode(UseCase.java:388)
at ncsa.analysis.types.UseCase.initializeFromElement(UseCase.java:339)
at ncsa.analysis.ui.actions.OpenUseCase.run(OpenUseCase.java:35)
at ncsa.gis.ui.listeners.PopupMenuActionOnDoubleClickListener.doubleClick(PopupMenuActionOnDoubleClickListener.java:56)
at org.eclipse.jface.viewers.StructuredViewer$1.run(StructuredViewer.java:799)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:37)
at org.eclipse.core.runtime.Platform.run(Platform.java:857)
at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:46)
at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:199)
at org.eclipse.jface.viewers.StructuredViewer.fireDoubleClick(StructuredViewer.java:797)
at org.eclipse.jface.viewers.AbstractTreeViewer.handleDoubleSelect(AbstractTreeViewer.java:1387)
at org.eclipse.jface.viewers.StructuredViewer$4.widgetDefaultSelected(StructuredViewer.java:1173)
at org.eclipse.jface.util.OpenStrategy.fireDefaultSelectionEvent(OpenStrategy.java:237)
at org.eclipse.jface.util.OpenStrategy.access$0(OpenStrategy.java:234)
at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:295)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:66)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:938)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3682)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3293)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2389)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2353)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2219)
at org.eclipse.ui.internal.Workbench$4.run(Workbench.java:466)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:289)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:461)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at ncsa.maeviz.rcp.Application.run(Application.java:26)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.internal.app.EclipseAppContainer.callMethod(EclipseAppContainer.java:572)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:171)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:106)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:76)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:363)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:176)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:508)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:447)
at org.eclipse.equinox.launcher.Main.run(Main.java:1173)
at org.eclipse.equinox.launcher.Main.main(Main.java:1148)