To reproduce
add Text
start inline editing
type some text
press Enter to commit
Following exception will be thrown

Exception in thread "JavaFX Application Thread" java.lang.AssertionError
at com.oracle.javafx.scenebuilder.kit.editor.panel.content.mode.EditModeController.inlineEditingDidRequestCommit(EditModeController.java:708)
at com.oracle.javafx.scenebuilder.kit.editor.panel.content.mode.EditModeController.access$900(EditModeController.java:88)
at com.oracle.javafx.scenebuilder.kit.editor.panel.content.mode.EditModeController$10.call(EditModeController.java:690)
at com.oracle.javafx.scenebuilder.kit.editor.panel.content.mode.EditModeController$10.call(EditModeController.java:687)
at com.oracle.javafx.scenebuilder.kit.editor.util.InlineEditController$1.handle(InlineEditController.java:151)
at com.oracle.javafx.scenebuilder.kit.editor.util.InlineEditController$1.handle(InlineEditController.java:141)
at com.sun.javafx.event.CompositeEventHandler$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.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.stage.PopupWindow$PopupEventRedirector.handleKeyEvent(PopupWindow.java:973)
at javafx.stage.PopupWindow$PopupEventRedirector.handleRedirectedEvent(PopupWindow.java:946)
at com.sun.javafx.event.EventRedirector.dispatchCapturingEvent(EventRedirector.java:106)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchCapturingEvent(CompositeEventDispatcher.java:43)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:52)
at com.sun.javafx.event.EventRedirector.redirectEvent(EventRedirector.java:124)
at com.sun.javafx.event.EventRedirector.dispatchCapturingEvent(EventRedirector.java:103)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchCapturingEvent(CompositeEventDispatcher.java:43)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:52)
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:203)
at javafx.scene.Scene$KeyHandler.process(Scene.java:3862)
at javafx.scene.Scene$KeyHandler.access$2100(Scene.java:3809)
at javafx.scene.Scene.impl_processKeyEvent(Scene.java:1993)
at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2450)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:170)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:123)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:197)
at com.sun.glass.ui.View.handleKeyEvent(View.java:517)
at com.sun.glass.ui.View.notifyKey(View.java:927)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$300(WinApplication.java:39)
at com.sun.glass.ui.win.WinApplication$4$1.run(WinApplication.java:112)
at java.lang.Thread.run(Thread.java:744)
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at com.oracle.javafx.scenebuilder.kit.editor.util.InlineEditController$InlineEditPopupController.onHidden(InlineEditController.java:213)
at com.oracle.javafx.scenebuilder.kit.editor.panel.util.AbstractPopupController$1.handle(AbstractPopupController.java:174)
at com.oracle.javafx.scenebuilder.kit.editor.panel.util.AbstractPopupController$1.handle(AbstractPopupController.java:169)
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.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:203)
at javafx.stage.Window.fireEvent(Window.java:1024)
at javafx.stage.Window$9.invalidated(Window.java:779)
at javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:109)
at javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:143)
at javafx.stage.Window.setShowing(Window.java:826)
at javafx.stage.Window.hide(Window.java:851)
at javafx.stage.PopupWindow.hide(PopupWindow.java:459)
at javafx.stage.PopupWindow.doAutoHide(PopupWindow.java:818)
at javafx.stage.PopupWindow$PopupEventRedirector.handleFocusUngrabEvent(PopupWindow.java:1021)
at javafx.stage.PopupWindow$PopupEventRedirector.handleRedirectedEvent(PopupWindow.java:958)
at com.sun.javafx.event.EventRedirector.dispatchCapturingEvent(EventRedirector.java:106)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchCapturingEvent(CompositeEventDispatcher.java:43)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:52)
at com.sun.javafx.event.EventRedirector.redirectEvent(EventRedirector.java:124)
at com.sun.javafx.event.EventRedirector.dispatchCapturingEvent(EventRedirector.java:103)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchCapturingEvent(CompositeEventDispatcher.java:43)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:52)
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:203)
at com.sun.javafx.stage.WindowPeerListener.focusUngrab(WindowPeerListener.java:97)
at com.sun.javafx.tk.quantum.GlassWindowEventHandler.run(GlassWindowEventHandler.java:92)
at com.sun.javafx.tk.quantum.GlassWindowEventHandler.run(GlassWindowEventHandler.java:39)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassWindowEventHandler.handleWindowEvent(GlassWindowEventHandler.java:130)
at com.sun.glass.ui.Window.handleWindowEvent(Window.java:1235)
at com.sun.glass.ui.Window.notifyFocusUngrab(Window.java:1219)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$300(WinApplication.java:39)
at com.sun.glass.ui.win.WinApplication$4$1.run(WinApplication.java:112)
at java.lang.Thread.run(Thread.java:744)