java.lang.NullPointerException
   at org.netbeans.modules.html.custom.conf.Configuration.store(Configuration.java:283)
   at org.netbeans.modules.html.custom.hints.AddElementFix.implement(AddElementFix.java:79)
   at org.netbeans.modules.csl.hints.infrastructure.FixWrapper.implement(FixWrapper.java:66)
   at org.netbeans.modules.editor.hints.HintsUI$1.run(HintsUI.java:847)
   at org.openide.util.RequestProcessor$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)