The code assumed that when adding chart items to lists, prev and next are initialized to null. Make this more robust. Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
The code assumed that when adding chart items to lists, prev and next are initialized to null. Make this more robust. Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>