What set of X events is expected to reach MaskableEventHandler in
client and get re- sent to xemacs? This is not the case for KeyPress
events. In Motif external client they do not reach external client
app if mouse pointer is in window of EmacsFrame widget. Otherwise
they get into window of EmacsShell widget (shared with external client
widget) and get re- sent. In Xt external client they never reach
external client app and xemacs never receives them.