How to apply a color or screen background to a tabulate (or table)cell?

[Daniel Pittman <daniel@rimspace.net>]

I would like to place a screen behind one cell of a table that I am
using at the moment. Ideally, rounding the corners of this screen would
also be possible, but I can live without that.

According to the comments in 'core-tbl.tex', color is to be done "as
required".  Is this accurate and, if so, is there no way to achieve
this?

Using \startbackrgound or \startframedtext both screw up the placement
of the text in the cell in fairly dramatic ways, most of the time, and
even when they work roughly right they only cover the text, not the full
height of the cell...

        Daniel

-- 
If you stick a knife nine inches into my back and pull it out
three inches, that is not progress.  Even if you pull it all the
way out, that is not progress...
        -- Malcolm X