java.lang.AssertionError
   at org.netbeans.spi.project.support.ant.SequentialPropertyEvaluator.stateChanged(SequentialPropertyEvaluator.java:160)
   at org.openide.util.WeakListenerImpl$Change.stateChanged(WeakListenerImpl.java:321)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:130)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:116)
   at org.netbeans.spi.project.support.ant.FilterPropertyProvider.setDelegate(FilterPropertyProvider.java:91)
   at org.netbeans.modules.javafx.project.JavaFXProject$ConfigPropertyProvider.run(JavaFXProject.java:238)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1369)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1907)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.AssertionError
   at org.openide.util.RequestProcessor.post(RequestProcessor.java:368)
   at org.netbeans.modules.javafx.project.JavaFXProject$ConfigPropertyProvider.propertyChange(JavaFXProject.java:233)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
   at org.netbeans.spi.project.support.ant.SequentialPropertyEvaluator.stateChanged(SequentialPropertyEvaluator.java:205)
   at org.openide.util.WeakListenerImpl$Change.stateChanged(WeakListenerImpl.java:321)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:130)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:116)
   at org.netbeans.spi.project.support.ant.ProjectProperties$PP$2.run(ProjectProperties.java:345)
   at org.netbeans.spi.project.support.ant.ProjectProperties$PP$2.run(ProjectProperties.java:343)
   at org.openide.util.Mutex.readAccess(Mutex.java:285)
   at org.netbeans.spi.project.support.ant.ProjectProperties$PP.fireChange(ProjectProperties.java:351)
   at org.netbeans.spi.project.support.ant.ProjectProperties$PP.put(ProjectProperties.java:220)
   at org.netbeans.spi.project.support.ant.ProjectProperties.putProperties(ProjectProperties.java:128)
   at org.netbeans.spi.project.support.ant.AntProjectHelper$6.run(AntProjectHelper.java:735)
   at org.netbeans.spi.project.support.ant.AntProjectHelper$6.run(AntProjectHelper.java:733)
   at org.openide.util.Mutex.writeAccess(Mutex.java:394)
   at org.netbeans.spi.project.support.ant.AntProjectHelper.putProperties(AntProjectHelper.java:733)
   at org.netbeans.modules.java.api.common.ant.UpdateHelper$2.run(UpdateHelper.java:114)
   at org.openide.util.Mutex.writeAccess(Mutex.java:469)
   at org.netbeans.modules.java.api.common.ant.UpdateHelper.putProperties(UpdateHelper.java:109)
   at org.netbeans.modules.javafx.project.ui.customizer.JavaFXProjectProperties.storeProperties(JavaFXProjectProperties.java:490)
   at org.netbeans.modules.javafx.project.ui.customizer.JavaFXProjectProperties.access$300(JavaFXProjectProperties.java:110)
   at org.netbeans.modules.javafx.project.ui.customizer.JavaFXProjectProperties$1.run(JavaFXProjectProperties.java:443)
   at org.netbeans.modules.javafx.project.ui.customizer.JavaFXProjectProperties$1.run(JavaFXProjectProperties.java:426)
   at org.openide.util.Mutex.writeAccess(Mutex.java:433)
   at org.netbeans.modules.javafx.project.ui.customizer.JavaFXProjectProperties.save(JavaFXProjectProperties.java:426)
   at org.netbeans.modules.javafx.project.ui.customizer.CustomizerProviderImpl$OptionListener.actionPerformed(CustomizerProviderImpl.java:164)
   at org.netbeans.modules.project.uiapi.CustomizerDialog$OptionListener$1.run(CustomizerDialog.java:246)
   at org.openide.util.Mutex.writeAccess(Mutex.java:394)
   at org.netbeans.modules.project.uiapi.CustomizerDialog$OptionListener.actionPerformed(CustomizerDialog.java:244)
   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.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
   at java.awt.Component.processMouseEvent(Component.java:6263)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3255)
   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:2475)
   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)