diff --git a/src/meshlab/glarea.cpp b/src/meshlab/glarea.cpp
index 5b19e6b5a..25ddcbf87 100644
--- a/src/meshlab/glarea.cpp
+++ b/src/meshlab/glarea.cpp
@@ -1303,7 +1303,7 @@ void GLArea::wheelEvent(QWheelEvent*e)
 	{
 
 		const int WHEEL_STEP = 120;
-		float notch = e->angleDelta().y()/ float(WHEEL_STEP);
+		float notch = e->angleDelta().x()/ float(WHEEL_STEP);
 		if (glas.wheelDirection)
 			notch *= -1;
 		switch(e->modifiers())