java.lang.NullPointerException: The folder parameter cannot be null
   at org.openide.util.Parameters.notNull(Parameters.java:89)
   at org.openide.filesystems.FileUtil.isParentOf(FileUtil.java:1444)
   at org.openide.filesystems.FileUtil.getRelativePath(FileUtil.java:1191)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStylePanel$ExternalStyleSheetItem.<init>(ExtractInlinedStylePanel.java:551)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStylePanel.createExternalStylesheetsModel(ExtractInlinedStylePanel.java:457)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStylePanel.initComponents(ExtractInlinedStylePanel.java:314)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStylePanel.<init>(ExtractInlinedStylePanel.java:103)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStyleRefactoringUI.getPanel(ExtractInlinedStyleRefactoringUI.java:89)
   at org.netbeans.modules.refactoring.spi.impl.ParametersPanel.<init>(ParametersPanel.java:156)
   at org.netbeans.modules.refactoring.spi.impl.RefactoringPanel.refresh(RefactoringPanel.java:681)
   at org.netbeans.modules.refactoring.spi.impl.RefactoringPanel.<init>(RefactoringPanel.java:169)
   at org.netbeans.modules.refactoring.spi.impl.RefactoringPanel.<init>(RefactoringPanel.java:157)
   at org.netbeans.modules.refactoring.spi.ui.UI.openRefactoringUI(UI.java:75)
   at org.netbeans.modules.html.editor.refactoring.HtmlSpecificRefactoringsProvider$2$1.run(HtmlSpecificRefactoringsProvider.java:147)
   at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
   at java.awt.EventQueue.access$500(EventQueue.java:97)
   at java.awt.EventQueue$3.run(EventQueue.java:709)
   at java.awt.EventQueue$3.run(EventQueue.java:703)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)