diff --git a/changelog.in b/changelog.in
index 16fedd6ee4..280e3be231 100755
--- a/changelog.in
+++ b/changelog.in
@@ -72,6 +72,7 @@ New stuff!
 Module: int
 What:   removed
 Rank:   minor
+Thanks: Jens Krueger
 [DESCRIPTION]
 The bool test operator has been removed from IntSet (it created
 problems and is actually useless for IntSet as they are always
diff --git a/gecode/kernel/shared-object.hpp b/gecode/kernel/shared-object.hpp
old mode 100644
new mode 100755
index 08b67a586e..a74534b35a
--- a/gecode/kernel/shared-object.hpp
+++ b/gecode/kernel/shared-object.hpp
@@ -80,7 +80,7 @@ namespace Gecode {
     /// Destructor that maintains reference count
     ~SharedHandle(void);
     /// Whether handle points to an object
-    operator bool(void) const;
+    explicit operator bool(void) const;
   protected:
     /// Access to the shared object
     SharedHandle::Object* object(void) const;