java.lang.IllegalStateException: Some of a set of deleted nodes are not present in the original ones.
See #15478; you may need to check that your Children.Keys keys are safely comparable.
i: 14
j: 13
This: org.openide.nodes.NodeMemberEvent[node=org.netbeans.modules.csl.navigation.ElementNode@5f3997f2[Name=, displayName=Ruby], add=false
  0 at 1 = org.netbeans.modules.csl.navigation.ElementNode@1081af19[Name=, displayName=image_tag]
  1 at 2 = org.netbeans.modules.csl.navigation.ElementNode@320e9ac6[Name=, displayName=t]
  2 at 3 = org.netbeans.modules.csl.navigation.ElementNode@5cd356d6[Name=, displayName=t]
  3 at 4 = org.netbeans.modules.csl.navigation.ElementNode@36ea2b36[Name=, displayName=render]
  4 at 5 = org.netbeans.modules.csl.navigation.ElementNode@47bb0264[Name=, displayName=t]
  5 at 6 = org.netbeans.modules.csl.navigation.ElementNode@469a1806[Name=, displayName=t]
  6 at 7 = org.netbeans.modules.csl.navigation.ElementNode@2e9f5620[Name=, displayName=t]
  7 at 8 = org.netbeans.modules.csl.navigat
        at org.openide.nodes.NodeMemberEvent.getDeltaIndices(NodeMemberEvent.java:176)
        at org.openide.explorer.view.VisualizerNode.childrenRemoved(VisualizerNode.java:372)
Caused: java.lang.reflect.InvocationTargetException
        at sun.reflect.GeneratedMethodAccessor45.invoke(GeneratedMethodAccessor45.java:0)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.openide.util.WeakListenerImpl$ProxyListener.invoke(WeakListenerImpl.java:451)
Caused: java.lang.reflect.UndeclaredThrowableException
        at $Proxy7.childrenRemoved(.java:0)
        at org.openide.nodes.Node.fireSubNodesChange(Node.java:1095)
        at org.openide.nodes.EntrySupport$Default.notifyRemove(EntrySupport.java:656)
        at org.openide.nodes.EntrySupport$Default.updateRemove(EntrySupport.java:384)
        at org.openide.nodes.EntrySupport$Default.setEntries(EntrySupport.java:338)
        at org.openide.nodes.Children$Keys$2.run(Children.java:1504)
        at org.openide.util.Mutex$1Exec.run(Mutex.java:1239)
        at org.openide.nodes.Children$ProjectManagerDeadlockDetector.execute(Children.java:1811)
        at org.openide.util.Mutex.postRequest(Mutex.java:1245)
        at org.openide.util.Mutex.postRequest(Mutex.java:1209)
        at org.openide.util.Mutex.postWriteRequest(Mutex.java:582)
        at org.openide.nodes.Children$Keys.applyKeys(Children.java:1513)
        at org.openide.nodes.Children$Keys.setKeys(Children.java:1457)
        at org.netbeans.modules.csl.navigation.ElementNode$ElementChildren.resetKeys(ElementNode.java:320)
        at org.netbeans.modules.csl.navigation.ElementNode.updateRecursively(ElementNode.java:266)
        at org.netbeans.modules.csl.navigation.ElementNode.updateRecursively(ElementNode.java:278)
        at org.netbeans.modules.csl.navigation.ClassMemberPanelUI$3.run(ClassMemberPanelUI.java:210)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:633)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:117)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)