diff --git a/src/Layer.cpp b/src/Layer.cpp
index 9a82d50..db5b7aa 100644
--- a/src/Layer.cpp
+++ b/src/Layer.cpp
@@ -18,6 +18,7 @@
 
 #include <set>
 
+using namespace mv;
 using namespace mv::gui;
 
 Layer::Layer(QObject* parent, const QString& title) :