there is no clear and unambiguous description for the dx Attribute in the case
where the XML character data within the 'tspan' element is null or space.
There is currently a difference in rendering between UAs, and errata filed as per URL above.
The current description appears to be here:
but afaict this possibility is not described.
In my view whether the character data within the 'tspan' element is null or
space it should be respected.
the rationale being that whereas in the attached example it is probable that
there is a primary key column it is easy to conceive circumstances where a key
would not be appropriate, or the key data may currently be unavailable, but one
wishes to display the available data.
Created attachment 33176 [details]
simple table example