diff --git a/src/core/timeline.cpp b/src/core/timeline.cpp
index 3120dacc1..6a417f57e 100644
--- a/src/core/timeline.cpp
+++ b/src/core/timeline.cpp
@@ -40,6 +40,10 @@
 #include "text_float.h"
 
 
+#if QT_VERSION < 0x040800
+#define MiddleButton MidButton
+#endif
+
 
 QPixmap * timeLine::s_timeLinePixmap = NULL;
 QPixmap * timeLine::s_posMarkerPixmap = NULL;