Here's one that seems to work even better, but I've given up entirely on the update_display device:
FW_Press = !echo "send 139">/proc/keypad; echo "send 139">/proc/keypad
This is just an extremely rapid double press of the menu button. Done very quickly like this the menu itself never gets drawn so there is no ghosting. Unless someone has a better mechanism I think this is probably my final solution.