Andrew Welch wrote:

  Hi!

> A thick plain white cell border that gives the appearance
> of a gap?

  That's the alternative I thought about ;-)  But I would like to know
what is the common approach to that problem before going further.  And
there are several columns and rows spanning, so I am afraid that would
add to that complexity.

  But yes, that's one possible solution I think.

  Thanks,

-- 
Florent Georges
http://www.fgeorges.org/