diff --git a/theme/list_lib.js b/theme/list_lib.js
index be2f969d5..684d92e13 100644
--- a/theme/list_lib.js
+++ b/theme/list_lib.js
@@ -1205,5 +1205,6 @@ function switchDives(e)
 }
 
 window.onresize = function(event) {
-      plot1.replot( { resetAxes: true } );
+      if (plot1)
+	      plot1.replot( { resetAxes: true } );
 };