diff --git a/src/msw/app.cpp b/src/msw/app.cpp
index 7c9aa3741f..f542a094a8 100644
--- a/src/msw/app.cpp
+++ b/src/msw/app.cpp
@@ -1116,7 +1116,7 @@ void wxApp::OnIdle(wxIdleEvent& event)
     // automated DC cache management: clear the cached DCs and bitmap
     // if it's likely that the app has finished with them, that is, we
     // get an idle event and we're not dragging anything.
-    if (!::GetKeyState(MK_LBUTTON) && !::GetKeyState(MK_MBUTTON) && ::GetKeyState(MK_RBUTTON))
+    if (!::GetKeyState(MK_LBUTTON) && !::GetKeyState(MK_MBUTTON) && !::GetKeyState(MK_RBUTTON))
         wxDC::ClearCache();
 #endif // wxUSE_DC_CACHEING