Allow chart to be null (to support usage from FXML).
Allow chart to be null (to support usage from FXML).
jfree/jfreechart,GitoMat/jfreechart,simon04/jfreechart,jfree/jfreechart,jfree/jfreechart,simon04/jfreechart,simon04/jfreechart,GitoMat/jfreechart,GitoMat/jfreechart,GitoMat/jfreechart,jfree/jfreechart,simon04/jfreechart