Translation tables

[Russell Shaw]

Hi,
On P.257 of "X Toolkit Intrinsics Programming Manual"
(Volume Four Motif Edition, OSF/Motif 1.2 Edition) it says
all <Key>b events not preceded by <Key>a events are discarded
with a translation table:

   <Key>a,<Key>b : something()
   <Key>         : else()

Why? Was there a design decision to do that, or was it just
a quirk that a particular algorithm happen to have?

It says <Key>b events will work as expected with:

   <Key>a,<Key>b : something()
   <Key>b        : else()
   <Key>         : else()