--- a/SystemBrowser.st	Thu Apr 13 14:43:00 2017 +0200
+++ b/SystemBrowser.st	Thu Apr 20 12:00:31 2017 +0200
@@ -5974,10 +5974,11 @@
                     tree := cls parseTreeFor:sel.
                     "/ walk
                     found :=
-                        tree usedLiterals contains:[:lit |
-                            lit isString
-                            and:[ lit isSymbol not
-                            and:[ checkLiteral value:lit ]]]
+                        tree notNil 
+                        and:[tree usedLiterals contains:[:lit |
+                                lit isString
+                                and:[ lit isSymbol not
+                                and:[ checkLiteral value:lit ]]]]
                 ].        
             ].        
         ].
@@ -5990,6 +5991,8 @@
      SystemBrowser findStringLiteral:'error' in:(Array with:Object) ignoreCase:false match:true
      SystemBrowser findStringLiteral:'error' in:(Array with:Object) ignoreCase:false match:false
     "
+
+    "Modified: / 20-04-2017 / 11:28:05 / stefan"
 !
 
 searchBlockForSymbol:aSymbol