java.lang.AssertionError
        at org.netbeans.modules.editor.structure.formatting.TagBasedLexerFormatter.reformat(TagBasedLexerFormatter.java:185)
        at org.netbeans.modules.editor.structure.formatting.TagBasedLexerFormatter.reformat(TagBasedLexerFormatter.java:160)
        at org.netbeans.modules.editor.structure.formatting.TagBasedLexerFormatter.process(TagBasedLexerFormatter.java:155)
        at org.netbeans.modules.html.editor.indent.HtmlIndentTask.reindent(HtmlIndentTask.java:68)
        at org.netbeans.modules.editor.indent.TaskHandler$MimeItem.runTask(TaskHandler.java:502)
        at org.netbeans.modules.editor.indent.TaskHandler.runTasks(TaskHandler.java:271)
        at org.netbeans.modules.editor.indent.IndentImpl.reformat(IndentImpl.java:293)
        at org.netbeans.modules.editor.indent.api.Reformat.reformat(Reformat.java:151)
        at org.netbeans.editor.ext.html.HTMLCompletionQuery$AutocompleteEndTagItem.reformat(HTMLCompletionQuery.java:729)
        at org.netbeans.editor.ext.html.HTMLCompletionQuery$HTMLResultItem.substituteText(HTMLCompletionQuery.java:643)
        at org.netbeans.editor.ext.html.HTMLCompletionQuery$EndTagItem.substituteText(HTMLCompletionQuery.java:785)
        at org.netbeans.editor.ext.html.HTMLCompletionQuery$HTMLResultItem.defaultAction(HTMLCompletionQuery.java:599)
        at org.netbeans.modules.editor.completion.CompletionImpl.dispatchKeyEvent(CompletionImpl.java:549)
        at org.netbeans.modules.editor.completion.CompletionImpl.keyPressed(CompletionImpl.java:350)
        at java.awt.AWTEventMulticaster.keyPressed(AWTEventMulticaster.java:192)
        at java.awt.AWTEventMulticaster.keyPressed(AWTEventMulticaster.java:191)
        at java.awt.Component.processKeyEvent(Component.java:5475)
        at javax.swing.JComponent.processKeyEvent(JComponent.java:2722)
        at java.awt.Component.processEvent(Component.java:5294)
        at java.awt.Container.processEvent(Container.java:1966)
        at java.awt.Component.dispatchEventImpl(Component.java:3984)
        at java.awt.Container.dispatchEventImpl(Container.java:2024)
        at java.awt.Component.dispatchEvent(Component.java:3819)
        at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1826)
        at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:681)
        at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:938)
        at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:810)
        at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:645)
        at java.awt.Component.dispatchEventImpl(Component.java:3857)
        at java.awt.Container.dispatchEventImpl(Container.java:2024)
        at java.awt.Window.dispatchEventImpl(Window.java:1791)
        at java.awt.Component.dispatchEvent(Component.java:3819)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)