code readapted to the fact that CometeTrendController.parseKey is static

src/main/java/fr/soleil/comete/bean/trend/view/renderer/TrendTreeCellRenderer.java

@@ -75,7 +75,7 @@ public class TrendTreeCellRenderer extends DefaultTreeCellRenderer {
                 int axis = -1;
                 CometeTrendController controller = ObjectUtils.recoverObject(controllerReference);
                 if (controller != null) {
-                    String key = controller.parseKey(getAttribute(value));
+                    String key = CometeTrendController.parseKey(getAttribute(value));
                     PlotProperties plotProperties = controller.getPlotProperties(key);
                     axis = plotProperties == null ? TrendFile.AXIS_NONE : plotProperties.getAxisChoice();
                 }