diff --git a/lib/main/core/picollection.h b/lib/main/core/picollection.h
index ac8d3017..93e58a6c 100644
--- a/lib/main/core/picollection.h
+++ b/lib/main/core/picollection.h
@@ -64,13 +64,13 @@ public:
 	
 	static bool addToGroup(const PIString & group, const PIObject * element);
 
-	class CollectionAdder {
+	class PIP_EXPORT CollectionAdder {
 	public:
 		CollectionAdder(const PIString & group, const PIObject * element, const PIString & name = PIString(), bool own = false);
 	};
 	
 protected:
-	struct Group {
+	struct PIP_EXPORT Group {
 		Group(const PIString & name_ = PIString()) {name = name_;}
 		PIString name;
 		PIVector<const PIObject * > elements;