--- a/AmbiguousMessage.st	Tue Sep 20 11:37:33 2016 +0100
+++ b/AmbiguousMessage.st	Mon Oct 03 12:44:41 2016 +0100
@@ -1,3 +1,5 @@
+"{ Encoding: utf8 }"
+
 "
  COPYRIGHT (c) 2010 by Jan Vrany, SWING Research Group. CTU in Prague
               All Rights Reserved
@@ -25,7 +27,9 @@
 "
 "{ Package: 'stx:libbasic' }"
 
-ProceedableError subclass:#AmbiguousMessage
+"{ NameSpace: Smalltalk }"
+
+ExecutionError subclass:#AmbiguousMessage
 	instanceVariableNames:''
 	classVariableNames:''
 	poolDictionaries:''
@@ -72,13 +76,23 @@
 "
 ! !
 
+!AmbiguousMessage class methodsFor:'testing'!
+
+isProgramError
+    "redefined in all exceptions which are programmer's errors,
+     and which should probably not be ignored.
+     I.e. a global error handler should reject and let a debugger get control."
+
+    ^ true
+! !
+
 !AmbiguousMessage class methodsFor:'documentation'!
 
 version_CVS
-    ^ '$Header: /cvs/stx/stx/libbasic/AmbiguousMessage.st,v 1.4 2013-12-24 10:40:54 cg Exp $'
+    ^ '$Header$'
 !
 
 version_SVN
-    ^ '$Id: AmbiguousMessage.st,v 1.4 2013-12-24 10:40:54 cg Exp $'
+    ^ '$Id$'
 ! !