javax.swing.text.BadLocationException: Modification not allowed
   at org.openide.text.CloneableEditorSupport$DocFilter.modificationNotAllowed(CloneableEditorSupport.java:2430)
   at org.openide.text.CloneableEditorSupport$DocFilter.checkModificationAllowed(CloneableEditorSupport.java:2424)
   at org.openide.text.CloneableEditorSupport$DocFilter.remove(CloneableEditorSupport.java:2380)
   at org.netbeans.editor.BaseDocument.remove(BaseDocument.java:937)
   at org.netbeans.modules.editor.indent.spi.Context.modifyIndent(Context.java:210)
   at org.netbeans.modules.web.indent.api.support.AbstractIndenter.modifyDocument(AbstractIndenter.java:1865)
   at org.netbeans.modules.web.indent.api.support.AbstractIndenter.applyIndents0(AbstractIndenter.java:1723)
   at org.netbeans.modules.web.indent.api.support.AbstractIndenter.access$2500(AbstractIndenter.java:82)
   at org.netbeans.modules.web.indent.api.support.AbstractIndenter$3.run(AbstractIndenter.java:1618)
   at org.netbeans.editor.GuardedDocument.runAtomic(GuardedDocument.java:323)
   at org.netbeans.modules.web.indent.api.support.AbstractIndenter.applyIndents(AbstractIndenter.java:1614)
   at org.netbeans.modules.web.indent.api.support.AbstractIndenter.applyIndentation(AbstractIndenter.java:450)
   at org.netbeans.modules.web.indent.api.support.AbstractIndenter.reindent(AbstractIndenter.java:234)
   at org.netbeans.modules.css.editor.indent.CssIndentTask.reindent(CssIndentTask.java:52)
   at org.netbeans.modules.editor.indent.TaskHandler$MimeItem.runTask(TaskHandler.java:546)
   at org.netbeans.modules.editor.indent.TaskHandler.runTasks(TaskHandler.java:316)
   at org.netbeans.modules.editor.indent.IndentImpl.reformat(IndentImpl.java:365)
   at org.netbeans.modules.editor.indent.api.Reformat.reformat(Reformat.java:154)
   at org.netbeans.editor.ActionFactory$FormatAction$1$1.run(ActionFactory.java:1683)
   at org.netbeans.editor.GuardedDocument.runAtomicAsUser(GuardedDocument.java:356)
   at org.netbeans.editor.ActionFactory$FormatAction$1.run(ActionFactory.java:1662)
   at org.netbeans.modules.progress.ui.RunOffEDTImpl$1.run(RunOffEDTImpl.java:169)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1423)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2033)