\startalignment etc. require text immediately after

[Ville Voipio <ville.voipio@kpatents.com>]

One phenomenon I have repeatedly come accross but not quite 
understood... If I have \startalignment, \startnarrower, etc., then 
there has to be text immediately after the start command.

As small example:

\startalignment[center]
\bTABLE
\bTR \bTD something \eTD \eTR
\eTABLE
\stopalignment

This should create a single-cell table in the middle of the page. It 
does not, the text is in the left.

If I add something small (a strut), then everything works fine:

\startalignment[center]
\strut
\bTABLE
\bTR \bTD something \eTD \eTR
\eTABLE
\stopalignment

Any text has the same effect as the strut. If the text is added to the 
end, it does not have any effect, i.e. the start has no effect. After 
some quick experimenting it seems evident that there has to be text 
after the start command. A figure or a table won't do. Why? And does 
this occur with any start-stop pair (sounds odd) or just with a few? And 
what is the kosher way of solving this problem?

This must be a FAQ, but I could not find the search terms to find an answer.

TIA,

- Ville