java.lang.AssertionError
        at org.netbeans.modules.web.client.tools.common.dbgp.DebuggerProxy.sendCommand(DebuggerProxy.java:304)
        at org.netbeans.modules.web.client.tools.common.dbgp.DebuggerProxy.getSource(DebuggerProxy.java:237)
        at org.netbeans.modules.web.client.tools.javascript.debugger.spi.JSAbstractExternalDebugger.getInputStreamForURLImpl(JSAbstractExternalDebugger.java:331)
        at org.netbeans.modules.web.client.tools.javascript.debugger.spi.JSAbstractExternalDebugger.getInputStreamForURLImpl(JSAbstractExternalDebugger.java:326)
        at org.netbeans.modules.web.client.tools.internetexplorer.IEJSDebugger.getInputStreamForURLImpl(IEJSDebugger.java:82)
        at org.netbeans.modules.web.client.tools.javascript.debugger.spi.JSAbstractDebugger.getInputStreamForURL(JSAbstractDebugger.java:188)
        at org.netbeans.modules.web.client.javascript.debugger.api.NbJSDebugger.getInputStreamForURL(NbJSDebugger.java:978)
        at org.netbeans.modules.web.client.javascript.debugger.api.NbJSDebuggerContentProvider$NbJSDebuggerContent.getInputStream(NbJSDebuggerContentProvider.java:75)
        at org.netbeans.modules.web.client.javascript.debugger.filesystem.URLFileObject.getInputStream(URLFileObject.java:266)
        at org.openide.filesystems.MIMESupport$CachedFileObject.getInputStream(MIMESupport.java:361)
        at org.netbeans.modules.openide.filesystems.declmime.MIMEResolverImpl$Type.accept(MIMEResolverImpl.java:626)
        at org.netbeans.modules.openide.filesystems.declmime.MIMEResolverImpl$Type.access$2000(MIMEResolverImpl.java:497)
        at org.netbeans.modules.openide.filesystems.declmime.MIMEResolverImpl$FileElement.resolve(MIMEResolverImpl.java:464)
        at org.netbeans.modules.openide.filesystems.declmime.MIMEResolverImpl$FileElement.access$700(MIMEResolverImpl.java:441)
        at org.netbeans.modules.openide.filesystems.declmime.MIMEResolverImpl$Impl.findMIMEType(MIMEResolverImpl.java:167)
        at org.openide.filesystems.MIMESupport$CachedFileObject.resolveMIME(MIMESupport.java:331)
        at org.openide.filesystems.MIMESupport$CachedFileObject.getMIMEType(MIMESupport.java:283)
        at org.openide.filesystems.MIMESupport.findMIMEType(MIMESupport.java:125)
        at org.openide.filesystems.FileUtil.getMIMEType(FileUtil.java:1120)
        at org.netbeans.api.java.source.JavaSource.forFileObject(JavaSource.java:441)
        at org.netbeans.api.java.source.support.OpenedEditors.stateChanged(OpenedEditors.java:161)
        at org.netbeans.api.java.source.support.OpenedEditors$1.propertyChange(OpenedEditors.java:86)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
        at org.netbeans.api.editor.EditorRegistry.fireEvents(EditorRegistry.java:478)
        at org.netbeans.api.editor.EditorRegistry.focusLost(EditorRegistry.java:318)
        at org.netbeans.api.editor.EditorRegistry$FocusL.focusLost(EditorRegistry.java:582)
        at java.awt.AWTEventMulticaster.focusLost(AWTEventMulticaster.java:213)
        at java.awt.AWTEventMulticaster.focusLost(AWTEventMulticaster.java:212)
        at java.awt.Component.processFocusEvent(Component.java:6026)
        at java.awt.Component.processEvent(Component.java:5890)
        at java.awt.Container.processEvent(Container.java:2023)
        at java.awt.Component.dispatchEventImpl(Component.java:4501)
        at java.awt.Container.dispatchEventImpl(Container.java:2081)
        at java.awt.Component.dispatchEvent(Component.java:4331)
        at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1848)
        at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:889)
        at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:562)
        at java.awt.Component.dispatchEventImpl(Component.java:4373)
        at java.awt.Container.dispatchEventImpl(Container.java:2081)
        at java.awt.Component.dispatchEvent(Component.java:4331)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.SentEvent.dispatch(SentEvent.java:55)
        at java.awt.DefaultKeyboardFocusManager$DefaultKeyboardFocusManagerSentEvent.dispatch(DefaultKeyboardFocusManager.java:183)
        at java.awt.DefaultKeyboardFocusManager.sendMessage(DefaultKeyboardFocusManager.java:210)
        at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:627)
        at java.awt.Component.dispatchEventImpl(Component.java:4373)
        at java.awt.Container.dispatchEventImpl(Container.java:2081)
        at java.awt.Window.dispatchEventImpl(Window.java:2458)
        at java.awt.Component.dispatchEvent(Component.java:4331)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.SequencedEvent.dispatch(SequencedEvent.java:101)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        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)