diff --git a/contrib/src/stc/ScintillaWX.cpp b/contrib/src/stc/ScintillaWX.cpp
index a0dbbad786..b41964f29a 100644
--- a/contrib/src/stc/ScintillaWX.cpp
+++ b/contrib/src/stc/ScintillaWX.cpp
@@ -573,6 +573,8 @@ void ScintillaWX::DoMouseWheel(int rotation, int delta,
         }
     }
     else { // otherwise just scroll the window
+        if ( !delta )
+            delta = 120;
         wheelRotation += rotation;
         lines = wheelRotation / delta;
         wheelRotation -= lines * delta;