diff --git a/src/App/PropertyExpressionEngine.cpp b/src/App/PropertyExpressionEngine.cpp
index 00b02935f..ed641e7b6 100644
--- a/src/App/PropertyExpressionEngine.cpp
+++ b/src/App/PropertyExpressionEngine.cpp
@@ -110,7 +110,7 @@ Property *PropertyExpressionEngine::Copy() const
     PropertyExpressionEngine * engine = new PropertyExpressionEngine();
 
     for (ExpressionMap::const_iterator it = expressions.begin(); it != expressions.end(); ++it)
-        engine->expressions[it->first] = ExpressionInfo(it->second);
+        engine->expressions[it->first] = ExpressionInfo(boost::shared_ptr<Expression>(it->second.expression->copy()), it->second.comment.c_str());
 
     engine->validator = validator;
 
@@ -125,7 +125,7 @@ void PropertyExpressionEngine::Paste(const Property &from)
     expressions.clear();
 
     for (ExpressionMap::const_iterator it = fromee->expressions.begin(); it != fromee->expressions.end(); ++it) {
-        expressions[it->first] = ExpressionInfo(it->second);
+        expressions[it->first] = ExpressionInfo(boost::shared_ptr<Expression>(it->second.expression->copy()), it->second.comment.c_str());
         expressionChanged(it->first);
     }