Exception in thread "AWT-EventQueue-0" java.lang.UnsupportedOperationException at java.base/java.util.Collections$EmptyMap.computeIfAbsent(Collections.java:4659) at org.simantics.scenegraph.ParentNode.getOrCreateNode(ParentNode.java:173) at org.simantics.diagram.handler.HighlightMode.paintSelectionFrames(HighlightMode.java:104) at org.simantics.diagram.handler.HighlightMode$2.run(HighlightMode.java:152) at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:313) at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:770) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721) at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)