Drop a Button.
Switch its Text property to multiline and enter a value on several lines. Validate.
Press Delete and you get the AssertionError (the Button is still selected).

     [java] Feb 24, 2014 5:04:24 PM com.oracle.javafx.scenebuilder.app.SceneBuilderApp$SceneBuilderUncaughtExceptionHandler uncaughtException
     [java] SEVERE: An exception was thrown:
     [java] java.lang.AssertionError
     [java] at com.oracle.javafx.scenebuilder.kit.editor.job.PrunePropertiesJob.<init>(PrunePropertiesJob.java:58)
     [java] at com.oracle.javafx.scenebuilder.kit.editor.job.SetDocumentRootJob.execute(SetDocumentRootJob.java:84)
     [java] at com.oracle.javafx.scenebuilder.kit.editor.job.BatchJob.execute(BatchJob.java:117)
     [java] at com.oracle.javafx.scenebuilder.kit.editor.job.DeleteObjectJob.execute(DeleteObjectJob.java:118)
     [java] at com.oracle.javafx.scenebuilder.kit.editor.job.v2.CompositeJob.execute(CompositeJob.java:98)
     [java] at com.oracle.javafx.scenebuilder.kit.editor.job.DeleteSelectionJob.execute(DeleteSelectionJob.java:62)
     [java] at com.oracle.javafx.scenebuilder.kit.editor.JobManager.executeJob(JobManager.java:181)
     [java] at com.oracle.javafx.scenebuilder.kit.editor.JobManager.push(JobManager.java:70)
     [java] at com.oracle.javafx.scenebuilder.kit.editor.EditorController.performEditAction(EditorController.java:949)
     [java] at com.oracle.javafx.scenebuilder.app.DocumentWindowController.performDelete(DocumentWindowController.java:1494)
     [java] at com.oracle.javafx.scenebuilder.app.DocumentWindowController.performEditAction(DocumentWindowController.java:816)
     [java] at com.oracle.javafx.scenebuilder.app.DocumentWindowController$1.handle(DocumentWindowController.java:300)
     [java] at com.oracle.javafx.scenebuilder.app.DocumentWindowController$1.handle(DocumentWindowController.java:239)
     [java] at com.sun.javafx.event.CompositeEventHandler$NormalEventFilterRecord.handleCapturingEvent(CompositeEventHandler.java:282)
     [java] at com.sun.javafx.event.CompositeEventHandler.dispatchCapturingEvent(CompositeEventHandler.java:98)
     [java] at com.sun.javafx.event.EventHandlerManager.dispatchCapturingEvent(EventHandlerManager.java:223)
     [java] at com.sun.javafx.event.EventHandlerManager.dispatchCapturingEvent(EventHandlerManager.java:180)
     [java] at com.sun.javafx.event.CompositeEventDispatcher.dispatchCapturingEvent(CompositeEventDispatcher.java:43)
     [java] at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:52)
     [java] at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
     [java] at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
     [java] at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
     [java] at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
     [java] at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
     [java] at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
     [java] at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
     [java] at javafx.event.Event.fireEvent(Event.java:204)
     [java] at javafx.scene.Scene$KeyHandler.process(Scene.java:3949)
     [java] at javafx.scene.Scene$KeyHandler.access$2100(Scene.java:3896)
     [java] at javafx.scene.Scene.impl_processKeyEvent(Scene.java:2036)
     [java] at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2493)
     [java] at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:170)
     [java] at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:123)
     [java] at java.security.AccessController.doPrivileged(Native Method)
     [java] at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:197)
     [java] at com.sun.glass.ui.View.handleKeyEvent(View.java:517)
     [java] at com.sun.glass.ui.View.notifyKey(View.java:927)
     [java]