Racing condition upon loading or refreshing
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
Exception in thread "AWT-EventQueue-0" java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:886)
at java.util.ArrayList$Itr.next(ArrayList.java:836)
at be.ugent.psb.modulegraphics.elements.Canvas.getRawDimension(Canvas.java:60)