Load the attached fxml file.
Select in Hierarchy the row Box.
Open in Inspector the layout section ==> you get the stack below if assertion if enabled, and the tool is in bad mood (e.g. cannot exit).

The root cause of the issue is here the fact the FXML refers to Point3D which is not resolved because we miss import statement such as <?import javafx.geometry.*?>.

SEVERE: An exception was thrown:
java.lang.AssertionError
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.editors.Point3DEditor.setValue(Point3DEditor.java:114)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.setEditorValueFromSelection(InspectorPanelController.java:1318)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.getInitializedPropertyEditor(InspectorPanelController.java:776)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.buildSection(InspectorPanelController.java:745)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.handleTitledPane(InspectorPanelController.java:1660)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController.access$200(InspectorPanelController.java:163)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController$3.changed(InspectorPanelController.java:530)
at com.oracle.javafx.scenebuilder.kit.editor.panel.inspector.InspectorPanelController$3.changed(InspectorPanelController.java:527)
at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:347)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
at javafx.beans.property.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.scene.control.TitledPane.setExpanded(TitledPane.java:160)
at com.sun.javafx.scene.control.behavior.TitledPaneBehavior.toggle(TitledPaneBehavior.java:184)
at com.sun.javafx.scene.control.skin.TitledPaneSkin$TitleRegion$2.handle(TitledPaneSkin.java:372)
at com.sun.javafx.scene.control.skin.TitledPaneSkin$TitleRegion$2.handle(TitledPaneSkin.java:364)
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.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:3746)
at javafx.scene.Scene$MouseHandler.access$1800(Scene.java:3471)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1695)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2486)
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)
at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at com.sun.glass.ui.gtk.GtkApplication.access$200(GtkApplication.java:48)
at com.sun.glass.ui.gtk.GtkApplication$6$1.run(GtkApplication.java:149)
at java.lang.Thread.run(Thread.java:744)