``` java.lang.IllegalArgumentException: Children: ...
# tornadofx
a
Copy code
java.lang.IllegalArgumentException: Children: duplicate children added: parent = VBox@5ee2d167
	at javafx.scene.Parent$2.onProposedChange(Parent.java:454)
	at com.sun.javafx.collections.VetoableListDecorator.addAll(VetoableListDecorator.java:249)
	at tornadofx.ListConversionListener.onChanged(Collections.kt:231)
	at com.sun.javafx.collections.ListListenerHelper$SingleChange.fireValueChangedEvent(ListListenerHelper.java:164)
	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.setAll(ModifiableObservableListBase.java:90)
	at inr.numass.control.BoardController$$special$$inlined$apply$lambda$2.invoke(BoardController.kt:67)