If XtGetActionKeysym is called after an
action procedure has been invoked by the Intrinsics and before that action
procedure returns, and if the event pointer has the same value as the event
pointer passed to that action routine, and if the event is a KeyPress
or KeyRelease event, then XtGetActionKeysym returns the KeySym that
matched the final event specification in the translation table and, if
/fImodifiers_return/fP is non-NULL, the modifier state actually used to
generate this KeySym; otherwise, if the event is a KeyPress or KeyRelease
event, then XtGetActionKeysym calls XtTranslateKeycode and returns
the results; else it returns NoSymbol and does not examine modifiers_return.