Open Unlock.fxml from SB samples
Select all children of root AnchorPane (in Hierarchy)
Uncheck their Visible property
Causes Assertion below:

Exception in thread "JavaFX Application Thread" java.lang.AssertionError
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.editors.BoundedDoubleEditor.getValueFromTextField(BoundedDoubleEditor.java:187)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.editors.BoundedDoubleEditor.getValue(BoundedDoubleEditor.java:155)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController$6.changed(InspectorPanelController.java:1099)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController$6.changed(InspectorPanelController.java:1094)
at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:176)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
at javafx.beans.property.BooleanPropertyBase.fireValueChangedEvent(BooleanPropertyBase.java:103)
at javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:110)
at javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:143)
at javafx.beans.property.BooleanProperty.setValue(BooleanProperty.java:77)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.editors.PropertyEditor.resetStates(PropertyEditor.java:648)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.editors.PropertyEditor.reset(PropertyEditor.java:440)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.editors.BoundedDoubleEditor.reset(BoundedDoubleEditor.java:172)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.makeOrResetPropertyEditor(InspectorPanelController.java:1565)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.resetPropertyEditor(InspectorPanelController.java:1513)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.reset(InspectorPanelController.java:593)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.updateInspector(InspectorPanelController.java:524)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.sceneGraphRevisionDidChange(InspectorPanelController.java:421)
at com.oracle.javafx.scenebuilder.kit.editor.panel.util.AbstractPanelController$2.changed(AbstractPanelController.java:179)
at com.oracle.javafx.scenebuilder.kit.editor.panel.util.AbstractPanelController$2.changed(AbstractPanelController.java:176)
at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:347)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
at javafx.beans.property.IntegerPropertyBase.fireValueChangedEvent(IntegerPropertyBase.java:106)
at javafx.beans.property.IntegerPropertyBase.markInvalid(IntegerPropertyBase.java:113)
at javafx.beans.property.IntegerPropertyBase.set(IntegerPropertyBase.java:146)
at com.oracle.javafx.scenebuilder.kit.fxom.FXOMDocument.refreshSceneGraph(FXOMDocument.java:263)
at com.oracle.javafx.scenebuilder.kit.fxom.FXOMDocument.endUpdate(FXOMDocument.java:243)
at com.oracle.javafx.scenebuilder.kit.editor.job.ModifySelectionJob.execute(ModifySelectionJob.java:81)
at com.oracle.javafx.scenebuilder.kit.editor.JobManager.executeJob(JobManager.java:174)
at com.oracle.javafx.scenebuilder.kit.editor.JobManager.push(JobManager.java:66)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.pushJob(InspectorPanelController.java:1132)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.setSelectedFXOMInstances(InspectorPanelController.java:1122)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.updateValueInModel(InspectorPanelController.java:1051)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.access$600(InspectorPanelController.java:142)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController$4.changed(InspectorPanelController.java:1031)
at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:176)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
at javafx.beans.property.ObjectPropertyBase.fireValueChangedEvent(ObjectPropertyBase.java:105)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:112)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:145)
at javafx.beans.property.ObjectProperty.setValue(ObjectProperty.java:69)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.editors.PropertyEditor.userUpdateValueProperty(PropertyEditor.java:472)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.editors.BooleanEditor$1.handle(BooleanEditor.java:60)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.editors.BooleanEditor$1.handle(BooleanEditor.java:57)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:204)
at javafx.scene.Node.fireEvent(Node.java:8175)
at javafx.scene.control.CheckBox.fire(CheckBox.java:235)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:204)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3689)
at javafx.scene.Scene$MouseHandler.access$1800(Scene.java:3414)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1676)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2467)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:314)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:243)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:345)
at com.sun.glass.ui.View.handleMouseEvent(View.java:526)
at com.sun.glass.ui.View.notifyMouse(View.java:898)