From 41359af1172d110fcf8d9986eeade6bf4e599b13 Mon Sep 17 00:00:00 2001
From: shawnlaffan <shawnlaffan@gmail.com>
Date: Mon, 5 Feb 2024 13:34:22 +1100
Subject: [PATCH] avoid an undef comparison warning

---
 lib/Biodiverse/GUI/Tabs/Spatial.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Biodiverse/GUI/Tabs/Spatial.pm b/lib/Biodiverse/GUI/Tabs/Spatial.pm
index c628ea1ea..35101aa28 100644
--- a/lib/Biodiverse/GUI/Tabs/Spatial.pm
+++ b/lib/Biodiverse/GUI/Tabs/Spatial.pm
@@ -1143,7 +1143,7 @@ sub on_selected_phylogeny_changed {
     my $dendro_tree = $self->{dendrogram}->get_cluster;
 
     #  don't trigger needless redraws
-    return if refaddr ($phylogeny) == refaddr ($dendro_tree);
+    return if ($dendro_tree && $phylogeny) && refaddr ($phylogeny) == refaddr ($dendro_tree);
 
     if ($self->{dendrogram}) {
         $self->{dendrogram}->clear;