It looks to me like JavaFX is in some place using an unmodifiable list which causes trouble.

The situation is this:
I have a Parent with a number of child nodes. I run through the list of child nodes and collect the nodes that fulfil my criteria for removal and add them to a regular ArrayList of nodes called nodesToRemove. I then invoke

theParentNode.getChildren().removeAll(nodesToRemove);

and then I get the exception shown below.

From the stack trace I have concluded that this bug is not caused by my own code. Rather, this bug seems to stem from the following code inside ListChangeBuilder (line 208:

else if (last != null && last.from == idx + 1) {
            last.from--;
            last.to--;
            last.removed.add(0, removed);
        }

Above the variable "last" is a SubChange which contains a list of what to remove and apparently this list is not modifiable. One could think that this would be caused by me supplying an unmodifiable list to the removeAll method, but this is not the case. Here is my code:

List<Node> removed = new ArrayList();
for(Node child : getChildren()) {
if(child instanceof Row) {
[...]
removed.add(row);
[...]
}
}
getChildren().removeAll(removed);


STACK TRACE

java.lang.UnsupportedOperationException
at java.util.Collections$UnmodifiableList.add(Collections.java:1314)
at javafx.collections.ListChangeBuilder.nextRemove(ListChangeBuilder.java:208)
at javafx.collections.ObservableListBase.nextRemove(ObservableListBase.java:150)
at javafx.collections.ModifiableObservableListBase.remove(ModifiableObservableListBase.java:181)
at com.sun.javafx.collections.ObservableListWrapper.removeAll(ObservableListWrapper.java:182)
at com.sun.javafx.collections.VetoableListDecorator.removeAll(VetoableListDecorator.java:267)
at com.intuism.ui.form.set.CollectionEditor.removeBlankEditors(CollectionEditor.java:334)
at com.intuism.ui.form.set.CollectionEditor$3.edited(CollectionEditor.java:156)
at com.intuism.ui.form.field.EditListeners.fireEdited(EditListeners.java:34)
at com.intuism.ui.form.field.EditListeners$1.changed(EditListeners.java:25)
at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:361)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
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.scene.control.ChoiceBox.setValue(ChoiceBox.java:286)
at com.wefend.observatory.friends.PhoneNumberEditor.contextualize(PhoneNumberEditor.java:129)
at com.intuism.core.settings.context.PriorityContext.contextualizeRecursively(PriorityContext.java:255)
at com.intuism.core.settings.context.PriorityContext.contextualizeRecursively(PriorityContext.java:266)
at com.intuism.core.settings.context.PriorityContext.introduceContextual(PriorityContext.java:223)
at com.intuism.core.settings.situation.NodeSettings$1.changed(NodeSettings.java:79)
at com.intuism.core.settings.situation.NodeSettings$1.changed(NodeSettings.java:67)
at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:182)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
at javafx.beans.property.ReadOnlyObjectWrapper$ReadOnlyPropertyImpl.fireValueChangedEvent(ReadOnlyObjectWrapper.java:176)
at javafx.beans.property.ReadOnlyObjectWrapper.fireValueChangedEvent(ReadOnlyObjectWrapper.java:142)
at javafx.scene.Node$ReadOnlyObjectWrapperManualFire.fireSuperValueChangedEvent(Node.java:806)
at javafx.scene.Node.invalidatedScenes(Node.java:856)
at javafx.scene.Node.setScenes(Node.java:894)
at javafx.scene.Parent.scenesChanged(Parent.java:654)
at javafx.scene.Node.invalidatedScenes(Node.java:828)
at javafx.scene.Node.setScenes(Node.java:894)
at javafx.scene.Parent.scenesChanged(Parent.java:654)
at javafx.scene.Node.invalidatedScenes(Node.java:828)
at javafx.scene.Node.setScenes(Node.java:894)
at javafx.scene.Parent$1.onChanged(Parent.java:271)
at com.sun.javafx.collections.TrackableObservableList.lambda$new$20(TrackableObservableList.java:45)
at com.sun.javafx.collections.TrackableObservableList$$Lambda$56/2068910691.onChanged(Unknown Source)
at com.sun.javafx.collections.ListListenerHelper$Generic.fireValueChangedEvent(ListListenerHelper.java:329)
at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
at javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
at javafx.collections.ListChangeBuilder.commit(ListChangeBuilder.java:482)
at javafx.collections.ListChangeBuilder.endChange(ListChangeBuilder.java:541)
at javafx.collections.ObservableListBase.endChange(ObservableListBase.java:205)
at javafx.collections.ModifiableObservableListBase.add(ModifiableObservableListBase.java:155)
at com.sun.javafx.collections.VetoableListDecorator.add(VetoableListDecorator.java:320)
at com.intuism.ui.form.set.CollectionEditor.readItem(CollectionEditor.java:167)
at com.intuism.ui.form.set.CollectionEditor$4.handle(CollectionEditor.java:286)
at com.intuism.ui.form.set.CollectionEditor$4.handle(CollectionEditor.java:281)
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.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8216)
at javafx.scene.control.Button.fire(Button.java:185)
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.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3724)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3452)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1728)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2461)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:348)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:273)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:382)
at com.sun.glass.ui.View.handleMouseEvent(View.java:553)
at com.sun.glass.ui.View.notifyMouse(View.java:925)