Always a problem sharing documents between the various office suites
and the more complex the construction the more challenging it is !!

Good to hear Calligra seems to do the job for this particular document
but you may find others don't fare as well - question is when you save
in Calligra does the user with MS Office find it renders correctly ?

FWIW - there can be the same problems between the various MS Office
suites too !

Ultimately the safest bet is for all collaborators having identical
office programs - and here is how the MicroSoft money machine keeps on
rolling

I refuse to work in MS Office when proof checking or
editing files for others. My results go back to them as an annotated
PDF, one of the few times that I do use an MS based PDF editor,
a programme from nuance.

I really appreciate your tips on handling .docx from others. Highly formatted
docs don't always translate well in OpenOffice, Abiword or LibreOffice as you
said, so I'll be trying Calligra and hoping for the best.

One sure way to view and edit .docx is with a free Microsoft Skydrive account.
It includes access to a limited but adequate online version of MS Word (plus
Excel and OneNote) that has always correctly shown .docx docs from others for
me. Maybe you're not Microsoft fans, as I am not particularly, but I've spent
enough money on Windows and Office over the years that I don't feel bad taking
advantage of their free stuff while using Linux, even understanding that in the
big picture it's marketing.