java.lang.AssertionError: project opened twice in a row, issue #236211 for C:\Sun\javaee7tutorialExamples2\examples\pom.xml
   at org.netbeans.modules.maven.NbMavenProjectImpl$Updater.attachAll(NbMavenProjectImpl.java:997)
   at org.netbeans.modules.maven.NbMavenProjectImpl.attachUpdater(NbMavenProjectImpl.java:494)
   at org.netbeans.modules.maven.ProjectOpenedHookImpl.projectOpened(ProjectOpenedHookImpl.java:160)
   at org.netbeans.spi.project.ui.ProjectOpenedHook$1.projectOpened(ProjectOpenedHook.java:85)
   at org.netbeans.modules.project.ui.OpenProjectList.notifyOpened(OpenProjectList.java:1298)
   at org.netbeans.modules.project.ui.OpenProjectList.doOpenProject(OpenProjectList.java:1379)
   at org.netbeans.modules.project.ui.OpenProjectList.open(OpenProjectList.java:823)
   at org.netbeans.modules.project.ui.groups.Group.open(Group.java:616)
   at org.netbeans.modules.project.ui.groups.Group.setActiveGroup(Group.java:206)
   at org.netbeans.modules.project.ui.groups.GroupsMenu$2.run(GroupsMenu.java:139)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1443)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2058)