fix serious repetitive exceptions if user closes colour dialog box without selecting...

diff --git a/src/jalview/gui/TreeCanvas.java b/src/jalview/gui/TreeCanvas.java
index ea2ef4d..328f02a 100755 (executable)
--- a/src/jalview/gui/TreeCanvas.java
+++ b/src/jalview/gui/TreeCanvas.java
@@ -682,8 +682,10 @@ public class TreeCanvas
       {
         Color col = JColorChooser.showDialog(this, "Select Sub-Tree Colour",
                                              highlightNode.color);
-
-        setColor(highlightNode, col);
+        if (col!=null)
+        {
+          setColor(highlightNode, col);
+        }
       }
       else
       if (evt.getClickCount() > 1)