java.lang.NullPointerException: The folder parameter cannot be null
   at org.openide.util.Parameters.notNull(Parameters.java:86)
   at org.openide.filesystems.FileUtil.isParentOf(FileUtil.java:1541)
   at org.openide.filesystems.FileUtil.getRelativePath(FileUtil.java:1315)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStylePanel$ExternalStyleSheetItem.<init>(ExtractInlinedStylePanel.java:486)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStylePanel.createExternalStylesheetsModel(ExtractInlinedStylePanel.java:392)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStylePanel.initComponents(ExtractInlinedStylePanel.java:272)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStylePanel.<init>(ExtractInlinedStylePanel.java:97)
   at org.netbeans.modules.html.editor.refactoring.ExtractInlinedStyleRefactoringUI.getPanel(ExtractInlinedStyleRefactoringUI.java:86)
   at org.netbeans.modules.refactoring.spi.impl.ParametersPanel.<init>(ParametersPanel.java:143)
   at org.netbeans.modules.refactoring.spi.impl.RefactoringPanel.refresh(RefactoringPanel.java:569)
   at org.netbeans.modules.refactoring.spi.impl.RefactoringPanel.<init>(RefactoringPanel.java:134)
   at org.netbeans.modules.refactoring.spi.impl.RefactoringPanel.<init>(RefactoringPanel.java:126)
   at org.netbeans.modules.refactoring.spi.ui.UI.openRefactoringUI(UI.java:72)
   at org.netbeans.modules.html.editor.refactoring.HtmlSpecificRefactoringsProvider.doExtractInlineStyle(HtmlSpecificRefactoringsProvider.java:112)
   at org.netbeans.modules.html.editor.refactoring.HtmlSpecificActionsImplementationFactory.doChangeParameters(HtmlSpecificActionsImplementationFactory.java:67)
   at org.netbeans.modules.html.editor.refactoring.actions.ExtractInlinedStyleAction.performAction(ExtractInlinedStyleAction.java:59)
   at org.netbeans.modules.html.editor.refactoring.actions.HtmlRefactoringGlobalAction.performAction(HtmlRefactoringGlobalAction.java:135)
   at org.openide.util.actions.NodeAction.performAction(NodeAction.java:297)
   at org.openide.util.actions.CallableSystemAction$1.run(CallableSystemAction.java:126)
   at org.openide.util.actions.ActionInvoker$1.run(ActionInvoker.java:92)
   at org.openide.util.actions.ActionInvoker.doPerformAction(ActionInvoker.java:113)
   at org.openide.util.actions.ActionInvoker.invokeAction(ActionInvoker.java:96)
   at org.openide.util.actions.CallableSystemAction.actionPerformed(CallableSystemAction.java:123)
   at org.openide.util.actions.NodeAction.superActionPerformed(NodeAction.java:280)
   at org.openide.util.actions.NodeAction.actionPerformed(NodeAction.java:273)
   at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
   at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
   at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
   at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
   at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
   at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1223)
   at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1264)
   at java.awt.Component.processMouseEvent(Component.java:6263)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
   at java.awt.Component.processEvent(Component.java:6028)
   at java.awt.Container.processEvent(Container.java:2041)
   at java.awt.Component.dispatchEventImpl(Component.java:4630)
   at java.awt.Container.dispatchEventImpl(Container.java:2099)
   at java.awt.Component.dispatchEvent(Component.java:4460)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4574)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4238)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4168)
   at java.awt.Container.dispatchEventImpl(Container.java:2085)
   at java.awt.Window.dispatchEventImpl(Window.java:2478)
   at java.awt.Component.dispatchEvent(Component.java:4460)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:133)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)