1. Compile and run the test below (a stage with three rectangles will appear).
2. Move mouse over the green rectangle (it should rise to the top of z-order).
3. Move mouse out of the green rectangle.

If AssignToBoundException (the stack is provided) is thrown the bug is reproduced.

The issue affects PhotoFlockr (aka FlickrFlockr) sample.

================================================================
import javafx.scene.Scene;
import javafx.scene.Node;
import javafx.scene.shape.Rectangle;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.scene.CustomNode;
import javafx.scene.Group;

Stage {
    visible: true
    scene: Scene {
        width: 200
        height: 200
        
        var rects = [ Rect { translateX: 70 translateY: 70 color: Color.LIGHTGREEN},
                      Rect { translateX: 40 translateY: 40 },
                      Rect { translateX: 100 translateY: 100 } ]

        content: [
            Group {
                content: bind rects[r | not r.selected]
            },
            Group {
                content: bind rects[r | r.selected]
            }
        ]
    }
}

class Rect extends CustomNode {
    var selected = false;
    var color = Color.LIGHTGRAY;

    public override function create(): Node {
        return Rectangle {
            width: 50
            height: 50
            fill: color
            stroke: Color.RED
            onMouseEntered: function(e) {
                selected = true;
            }
            onMouseExited: function(e) {
                selected = false;
            }
        }
    }
}
=================================================================================


Exception in trigger:
com.sun.javafx.runtime.AssignToBoundException: Cannot mutate bound sequence
        at com.sun.javafx.runtime.location.SequenceVariable.ensureNotBound(SequenceVariable.java:272)
        at com.sun.javafx.runtime.location.SequenceVariable.replaceSlice(SequenceVariable.java:323)
        at javafx.scene.Group$1.onChange(Group.fx:143)
        at com.sun.javafx.runtime.location.SequenceVariable$4.action(SequenceVariable.java:218)
        at com.sun.javafx.runtime.location.SequenceVariable$4.action(SequenceVariable.java:215)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:55)
        at com.sun.javafx.runtime.location.SequenceVariable.notifyListeners(SequenceVariable.java:215)
        at com.sun.javafx.runtime.location.SequenceVariable$BoundLocationInfo$2.onChange(SequenceVariable.java:454)
        at com.sun.javafx.runtime.sequence.AbstractBoundSequence.notifyListeners(AbstractBoundSequence.java:140)
        at com.sun.javafx.runtime.sequence.AbstractBoundSequence.updateSlice(AbstractBoundSequence.java:73)
        at com.sun.javafx.runtime.sequence.AbstractBoundComprehension$1.onChange(AbstractBoundComprehension.java:114)
        at com.sun.javafx.runtime.sequence.AbstractBoundSequence.notifyListeners(AbstractBoundSequence.java:140)
        at com.sun.javafx.runtime.sequence.AbstractBoundSequence.updateSlice(AbstractBoundSequence.java:73)
        at com.sun.javafx.runtime.sequence.BoundCompositeSequence$MyListener.onChange(BoundCompositeSequence.java:185)
        at com.sun.javafx.runtime.location.SequenceVariable$4.action(SequenceVariable.java:218)
        at com.sun.javafx.runtime.location.SequenceVariable$4.action(SequenceVariable.java:215)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:55)
        at com.sun.javafx.runtime.location.SequenceVariable.notifyListeners(SequenceVariable.java:215)
        at com.sun.javafx.runtime.location.SequenceVariable.bind(SequenceVariable.java:233)
        at com.sun.javafx.runtime.location.SequenceVariable.rebind(SequenceVariable.java:240)
        at com.sun.javafx.runtime.location.IndirectSequenceExpression$1.onChange(IndirectSequenceExpression.java:50)
        at com.sun.javafx.runtime.location.IndirectSequenceExpression$1.onChange(IndirectSequenceExpression.java:48)
        at com.sun.javafx.runtime.location.ObjectVariable$2.action(ObjectVariable.java:165)
        at com.sun.javafx.runtime.location.ObjectVariable$2.action(ObjectVariable.java:162)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:55)
        at com.sun.javafx.runtime.location.ObjectVariable.notifyListeners(ObjectVariable.java:162)
        at com.sun.javafx.runtime.location.ObjectVariable.replaceValue(ObjectVariable.java:117)
        at com.sun.javafx.runtime.location.ObjectVariable.update(ObjectVariable.java:145)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:179)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:60)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidate(AbstractLocation.java:115)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:177)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:60)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidate(AbstractLocation.java:115)
        at com.sun.javafx.runtime.location.AbstractVariable.invalidate(AbstractVariable.java:177)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:141)
        at com.sun.javafx.runtime.location.AbstractLocation$4.action(AbstractLocation.java:135)
        at com.sun.javafx.runtime.util.AbstractLinkable.iterate(AbstractLinkable.java:60)
        at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:162)
        at com.sun.javafx.runtime.location.BooleanVariable.notifyListeners(BooleanVariable.java:174)
        at com.sun.javafx.runtime.location.BooleanVariable.replaceValue(BooleanVariable.java:86)
        at com.sun.javafx.runtime.location.BooleanVariable.setAsBoolean(BooleanVariable.java:111)
        at fxbug.Main$Rect$2.lambda(Main.fx:46)
        at fxbug.Main$Rect$2.lambda(Main.fx:46)
        at fxbug.Main$Rect$2.invoke(Main.fx:45)
        at fxbug.Main$Rect$2.invoke(Main.fx:45)
        at fxbug.Main$Rect$2.invoke(Main.fx:45)
        at fxbug.Main$Rect$2.invoke(Main.fx:45)
        at javafx.scene.Node$1SGMouseAdapter$anon26.call(Node.fx:1098)
        at javafx.scene.Node$1SGMouseAdapter$anon26.mouseExited(Node.fx:1112)
        at com.sun.scenario.scenegraph.SGNode.processMouseEvent(SGNode.java:485)
        at com.sun.scenario.scenegraph.JSGPanel$MouseInputDispatcher.deliverEnterExit(JSGPanel.java:276)
        at com.sun.scenario.scenegraph.JSGPanel$MouseInputDispatcher.mouseMoved(JSGPanel.java:396)
        at com.sun.scenario.scenegraph.JSGPanel$MouseInputDispatcher.mouseMoved(JSGPanel.java:386)
        at java.awt.Component.processMouseMotionEvent(Component.java:6179)
        at javax.swing.JComponent.processMouseMotionEvent(JComponent.java:3283)
        at java.awt.Component.processEvent(Component.java:5903)
        at java.awt.Container.processEvent(Container.java:2023)
        at java.awt.Component.dispatchEventImpl(Component.java:4501)
        at java.awt.Container.dispatchEventImpl(Container.java:2081)
        at java.awt.Component.dispatchEvent(Component.java:4331)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4301)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3978)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3895)
        at java.awt.Container.dispatchEventImpl(Container.java:2067)
        at java.awt.Window.dispatchEventImpl(Window.java:2458)
        at java.awt.Component.dispatchEvent(Component.java:4331)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        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)