java.lang.IllegalStateException: Problem in some module which uses Window System: Window System API is required to be called from AWT thread only, see http://core.netbeans.org/proposals/threading/
   at org.netbeans.core.windows.WindowManagerImpl.warnIfNotInEDT(WindowManagerImpl.java:1709)
   at org.netbeans.core.windows.WindowManagerImpl.topComponentDisplayNameChanged(WindowManagerImpl.java:1316)
   at org.openide.windows.TopComponent.setName(TopComponent.java:963)
   at org.netbeans.modules.merge.builtin.visualizer.MergeDialogComponent.refreshName(MergeDialogComponent.java:393)
   at org.netbeans.modules.merge.builtin.visualizer.MergeDialogComponent.access$1000(MergeDialogComponent.java:89)
   at org.netbeans.modules.merge.builtin.visualizer.MergeDialogComponent$MergeNode.propertyChange(MergeDialogComponent.java:531)
   at org.openide.util.WeakListenerImpl$PropertyChange.propertyChange(WeakListenerImpl.java:196)
   at java.beans.PropertyChangeSupport.fire(PropertyChangeSupport.java:335)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:327)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:263)
   at java.awt.Component.firePropertyChange(Component.java:8381)
   at org.netbeans.modules.merge.builtin.visualizer.MergePanel.setNeedsSaveState(MergePanel.java:508)
   at org.netbeans.modules.merge.builtin.visualizer.MergeControl.vetoableChange(MergeControl.java:365)
   at org.openide.util.WeakListenerImpl$VetoableChange.vetoableChange(WeakListenerImpl.java:228)
   at java.beans.VetoableChangeSupport.fireVetoableChange(VetoableChangeSupport.java:375)
   at java.beans.VetoableChangeSupport.fireVetoableChange(VetoableChangeSupport.java:271)
   at javax.swing.JComponent.fireVetoableChange(JComponent.java:4537)
   at org.netbeans.modules.merge.builtin.visualizer.MergeDialogComponent.access$1200(MergeDialogComponent.java:89)
   at org.netbeans.modules.merge.builtin.visualizer.MergeDialogComponent$MergeNode$SaveCookieImpl.save(MergeDialogComponent.java:539)
   at org.openide.actions.SaveAction.performAction(SaveAction.java:132)
   at org.openide.actions.SaveAction.performAction(SaveAction.java:102)
   at org.openide.actions.SaveAction$Delegate.actionPerformed(SaveAction.java:249)
   at org.openide.awt.ContextAction$Performer.actionPerformed(ContextAction.java:231)
   at org.openide.awt.ContextManager.actionPerformed(ContextManager.java:247)
   at org.openide.awt.ContextAction.actionPerformed(ContextAction.java:109)
   at org.openide.util.actions.ActionInvoker$1.run(ActionInvoker.java:93)
   at org.openide.util.actions.ActionInvoker$ActionRunnable.actionPerformed(ActionInvoker.java:162)
   at org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:109)
   at org.netbeans.modules.openide.actions.ActionsBridgeImpl.invokeAction(ActionsBridgeImpl.java:60)
   at org.openide.util.actions.ActionInvoker$ActionRunnable.doRun(ActionInvoker.java:153)
   at org.openide.util.actions.ActionInvoker$2.run(ActionInvoker.java:110)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1452)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2032)