compctl tips needed on words with common prefix

[Paul Lew <lew@xxxxxxxxxxxxxxxxxx>]

I am trying to define the following compctl:

	compctl -k "(ci co construct cinema)" xxx

This works fine.  Now I am adding extra:

	compctl -k "(ci co construct cinema)" \
		-x "r[co,;]" -k "(co1 co2 co3)" \
		- "r[construct,;]" -k "(cons1 cons2)" -- xxx 

I could not get 'construct' to be completed by <TAB> because the 'co'
is recognized first, i.e.,

	xxx c<TAB>
ci   cinema   co   construct

	xxx co<TAB>
co1  co1   co3

	xxx con<TAB>
nothing

  Any trick to this?  Thanks in advance...