--- loncom/xml/lonplot.pm	2018/09/26 14:52:43	1.179
+++ loncom/xml/lonplot.pm	2018/09/26 15:24:46	1.180
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Dynamic plot
 #
-# $Id: lonplot.pm,v 1.179 2018/09/26 14:52:43 raeburn Exp $
+# $Id: lonplot.pm,v 1.180 2018/09/26 15:24:46 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -532,7 +532,7 @@ my %axis_defaults =
          },
      yformat      => {
          default     => 'on',
-         test        => sub {$_[0]=~/^(on|off|\d+(f|F|e|E))$/},
+         test        => sub {$_[0]=~/^(on|off|\d+(f|F|e|E|P(|\s*\Q\0317\0200\E)))$/},
          description => 'Y-axis number formatting',
          edit_type   => 'choice',
          choices     => ['on', 'off', '2e', '2f'],