java.util.ConcurrentModificationException
        at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
        at java.util.AbstractList$Itr.next(AbstractList.java:343)
        at org.netbeans.modules.cnd.makeproject.ui.options.ParserSettingsPanel$3.runImpl(ParserSettingsPanel.java:192)
        at org.netbeans.modules.cnd.utils.NamedRunnable.run(NamedRunnable.java:59)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:602)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1084)
Caused: org.openide.util.RequestProcessor$FastItem: task failed due to: java.util.ConcurrentModificationException