diff --git a/lib/Biodiverse/GUI/Dendrogram.pm b/lib/Biodiverse/GUI/Dendrogram.pm
index ed2be02ae..0cd9c3087 100644
--- a/lib/Biodiverse/GUI/Dendrogram.pm
+++ b/lib/Biodiverse/GUI/Dendrogram.pm
@@ -1627,16 +1627,20 @@ sub on_map_index_combo_changed {
     my $iter  = $combo->get_active_iter;
 
     if ($iter) {
-
         $index = $combo->get_model->get($iter, 0);
         $self->{analysis_list_index} = $index;
 
-        my @minmax = $self->get_plot_min_max_values;
-        $self->{analysis_min} = $minmax[0];
-        $self->{analysis_max} = $minmax[1];
+        my $map = $self->{map};
+
+        my @minmax = $self->get_parent_tab->set_plot_min_max_values;
 
         # say "[Dendrogram] Setting grid to use index $index";
-        $self->{map}->set_legend_min_max(@minmax);
+        #  must set this before legend min max
+        $map->set_legend_colour_mode_from_list_and_index (
+            list  => $self->{analysis_list_name},
+            index => $self->{analysis_list_index},
+        );
+        $map->set_legend_min_max(@minmax);
         $self->get_parent_tab->on_colour_mode_changed;
 
         $self->set_cluster_colour_mode(value => "list-values");
@@ -1644,7 +1648,7 @@ sub on_map_index_combo_changed {
 
         $self->recolour_cluster_lines($self->get_processed_nodes);
 
-        $self->{map}->update_legend;
+        $map->update_legend;
     }
     else {
         $self->{analysis_list_index} = undef;
@@ -1688,7 +1692,7 @@ sub set_plot_min_max_values {
     $self->{analysis_min} = $min;
     $self->{analysis_max} = $max;
 
-    return;
+    return wantarray ? ($min, $max) : [$min, $max];
 }
 
 sub get_plot_min_max_values {
diff --git a/lib/Biodiverse/GUI/Grid.pm b/lib/Biodiverse/GUI/Grid.pm
index f3a7183cf..6dfad79ec 100644
--- a/lib/Biodiverse/GUI/Grid.pm
+++ b/lib/Biodiverse/GUI/Grid.pm
@@ -227,6 +227,11 @@ sub update_legend {
     return;
 }
 
+sub set_legend_colour_mode_from_list_and_index {
+    my $self = shift;
+    return $self->get_legend->set_colour_mode_from_list_and_index(@_);
+}
+
 sub set_legend_mode {
     my $self = shift;
     my $mode = shift;
diff --git a/lib/Biodiverse/GUI/Legend.pm b/lib/Biodiverse/GUI/Legend.pm
index 83ea2e307..1e213e451 100644
--- a/lib/Biodiverse/GUI/Legend.pm
+++ b/lib/Biodiverse/GUI/Legend.pm
@@ -753,6 +753,9 @@ sub get_colour_ratio {
 
     state $centre_colour = Gtk2::Gdk::Color->parse('#ffffbf');
 
+    #  Perhaps should handle cases where min or max are zero,
+    #  but those should not be passed anyway so an error is
+    #  appropriate.
     my $extreme = exp (max (abs log $min, log $max));
 
     return $centre_colour
diff --git a/lib/Biodiverse/GUI/Tabs/Clustering.pm b/lib/Biodiverse/GUI/Tabs/Clustering.pm
index 573904d26..b4a8d7b19 100644
--- a/lib/Biodiverse/GUI/Tabs/Clustering.pm
+++ b/lib/Biodiverse/GUI/Tabs/Clustering.pm
@@ -1899,6 +1899,8 @@ sub recolour {
     #  need to update the grid before the tree else the grid is not changed properly
     $self->set_plot_min_max_values;
     $self->{grid}->set_legend_mode($self->{colour_mode});
+    # $self->{grid}->set_legend_min_max($self->get_plot_min_max_values);
+    # $self->{grid}->update_legend();
 
     $self->{dendrogram}->recolour();
     if ($args{all_elements}) {
@@ -1915,22 +1917,18 @@ sub set_plot_min_max_values {
 
     return if ! defined $list || ! defined $index;
 
-    my $stats = $self->{stats}{$list}{$index};
-    if (not $stats) {
-        $stats = $self->{output_ref}->get_list_stats (
+    my $stats = $self->{stats}{$list}{$index}
+        //=  $self->{output_ref}->get_list_stats (
             list  => $list,
             index => $index,
         );
-    }
 
     $self->{plot_min_value} = $stats->{$self->{PLOT_STAT_MIN} || 'MIN'};
     $self->{plot_max_value} = $stats->{$self->{PLOT_STAT_MAX} || 'MAX'};
 
     $self->set_legend_ltgt_flags ($stats);
 
-    $self->{dendrogram}->set_plot_min_max_values ($self->get_plot_min_max_values);
-
-    return;
+    return $self->{dendrogram}->set_plot_min_max_values ($self->get_plot_min_max_values);
 }
 
 #  Same as the version in Spatial.pm except it calls