selectiongroup could be null

diff --git a/src/jalview/gui/PCAPanel.java b/src/jalview/gui/PCAPanel.java
index 8e0bc37..d0b3bbc 100755 (executable)
--- a/src/jalview/gui/PCAPanel.java
+++ b/src/jalview/gui/PCAPanel.java
@@ -23,7 +23,7 @@ public class PCAPanel extends GPCAPanel implements Runnable
   public PCAPanel(AlignViewport av, SequenceI[] s) {\r
 \r
     this.av = av;\r
-    if(av.getSelectionGroup().getSize()>3)\r
+    if(av.getSelectionGroup()!=null && av.getSelectionGroup().getSize()>3)\r
     {\r
       s = new Sequence[av.getSelectionGroup().getSize()];\r
       for(int i=0; i<s.length; i++)\r