Merge pull request #467 from plotly/fix_issue_439

fix issue #439

Author: gilbertogalvis

plotly/plotlyfig.m

@@ -1153,6 +1153,7 @@ function delete(obj)
                         ||  strcmpi(fieldname,'scatter') ||  strcmpi(fieldname,'line')...
                         ||  strcmpi(fieldname,'scattergeo') ||  strcmpi(fieldname,'scattermapbox')...
                         ||  strcmpi(fieldname,'scatterternary') ||  strcmpi(fieldname,'colorbar')...
+                        ||  strcmpi(fieldname,'contours')...
                         )
                         fprintf(['\nWhoops! ' exception.message(1:end-1) ' in ' fieldname '\n\n']);
                     end