diff --git a/panda/src/wgldisplay/wglGraphicsWindow.cxx b/panda/src/wgldisplay/wglGraphicsWindow.cxx
index 30328270e3..68976d74cd 100644
--- a/panda/src/wgldisplay/wglGraphicsWindow.cxx
+++ b/panda/src/wgldisplay/wglGraphicsWindow.cxx
@@ -1355,6 +1355,7 @@ window_proc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam) {
         GetCursorPos(&point);
         ScreenToClient(hwnd, &point);
         handle_keypress(lookup_key(wparam), point.x, point.y);
+        return 0;
       }
 
     case WM_SYSKEYUP: