fix for go evidence code being blank

git-svn-id: svn+ssh://svn.internal.sanger.ac.uk/repos/svn/pathsoft/artemis/trunk@7165 ee4ac58c-ac51-4696-9907-e4b3aa274f04

uk/ac/sanger/artemis/components/genebuilder/cv/GoBox.java

@@ -239,7 +239,9 @@ class GoBox extends AbstractCvBox
       return true;
     
     old = getField("evidence=", origQualifierString);
-    if(!old.equalsIgnoreCase(evidenceCodes[2][ evidenceList.getSelectedIndex() ]))
+    
+    if(evidenceList.getSelectedIndex() > -1 &&
+       !old.equalsIgnoreCase(evidenceCodes[2][ evidenceList.getSelectedIndex() ]))
       return true;
     
     old = getField("qualifier=", origQualifierString);