java.lang.NullPointerException
   at org.netbeans.modules.web.webkit.debugging.api.css.CSS.getMatchedStyles(CSS.java:365)
   at org.netbeans.modules.web.inspect.webkit.ui.CSSStylesSelectionPanel.updateMatchedRules(CSSStylesSelectionPanel.java:639)
   at org.netbeans.modules.web.inspect.webkit.ui.CSSStylesSelectionPanel$9.run(CSSStylesSelectionPanel.java:628)
   at org.openide.util.RequestProcessor$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)