fixed tree building exception when one residue or a single column of residues is...

[jalview.git] / src / jalview / gui / AlignFrame.java

diff --git a/src/jalview/gui/AlignFrame.java b/src/jalview/gui/AlignFrame.java
index 807b6e3..ef228df 100755 (executable)
--- a/src/jalview/gui/AlignFrame.java
+++ b/src/jalview/gui/AlignFrame.java
@@ -2166,9 +2166,15 @@ public class AlignFrame
   {
     TreePanel tp;
 
-    if ( (viewport.getSelectionGroup() != null) &&
-        (viewport.getSelectionGroup().getSize(false) > 3))
-    {
+    if (viewport.getSelectionGroup() != null) {
+      if (viewport.getSelectionGroup().getSize(false) < 3) {
+        JOptionPane.showMessageDialog(Desktop.desktop,
+                                      "You need to have more than two sequences selected to build a tree!",
+                                      "Not enough sequences",
+                                      JOptionPane.WARNING_MESSAGE);
+        return;
+      }
+
       int s = 0;
       SequenceGroup sg = viewport.getSelectionGroup();