Hello all,
I think you might have noticed that I am getting a bit fed up with the complexity and lack of information of doing something as simple as changing the order and contents of the "open with" list. So I decided to approach the problem from another side, going at it using the "gordian knot" method: I just removed the OpenOffice writers .desktop entry (from /usr/share/applications). Luckily, that worked (I have no idea what I would have done otherwise), its entry in the "open with" list was gone.
So, I placed it back and pretty-much gutted it, after which I started to build it up again (binary search much?). I now have a single entry which causes both its application icon to disappear (even though I did not thouch the "Icon=" entry), as well as its in-or-outof the "opens with" list:
-- Current contents -- [Desktop Entry] Version= Terminal= Icon= Exec= Name= GenericName= Type=Application