java.lang.NullPointerException
   at org.netbeans.core.browser.xulrunner.WebBrowserImpl.createDisabledLabel(WebBrowserImpl.java:167)
   at org.netbeans.core.browser.xulrunner.WebBrowserImpl.access$100(WebBrowserImpl.java:88)
   at org.netbeans.core.browser.xulrunner.WebBrowserImpl$1.stateChanged(WebBrowserImpl.java:134)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:133)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:119)
   at org.netbeans.core.browser.xulrunner.BrowserManager$1.preferenceChange(BrowserManager.java:79)
   at java.util.prefs.AbstractPreferences$EventDispatchThread.run(AbstractPreferences.java:1475)