I don't want to intrude too much in this thread, but suppose Xara made it possible to deselect the option to install the Magix photo editor... I don't think Magix would be very happy about this. And it wouldn't make the Xara-Magix relations much better I think. AFAIK the Magix photo editor is the only "tangible" presence of Magix in the Xtreme software. Giving users the option to remove this presence is almost like indicating you don't want to work with Magix :\
Making the Magix photo editor part of the "core" install, but making XPE optional obviously isn't going to work for Xara.

I'm not standing in their shoes, but I think these considerations also play a part in this matter.