diff --git a/panda/src/tform/mouseWatcherParameter.I b/panda/src/tform/mouseWatcherParameter.I
index bfb879c7ac..fda8135a67 100644
--- a/panda/src/tform/mouseWatcherParameter.I
+++ b/panda/src/tform/mouseWatcherParameter.I
@@ -20,6 +20,7 @@
 ////////////////////////////////////////////////////////////////////
 INLINE MouseWatcherParameter::
 MouseWatcherParameter() {
+  _keycode = 0;
   _flags = 0;
 }