It's beyond me to understand why JustSystems, the Japanese company that bought XMetaL from Blast Radius, insists on this dependency.
An XMetaL developer doesn't need all the bells, whistles, and bugs that is Visual Studio, he needs a reasonably flexible scripting environment, easy access to modifying CSS stylesheets, writing (XML-based) toolbars and customizations, as well as the occasional form or dialog.
The thing is, different developers have different preferences. While I do believe that there are people that actually like Visual Studio .Net, not all of us do. Maybe we prefer other languages, or maybe we believe that forcing us to use the same tool for everything just isn't the right way to go. After all, even if you own an 18-wheel truck, you don't use it to drive to the supermarket to buy groceries. You use a car or a bus or a bike. Something that doesn't get in the way.
Because that's what Visual Studio does. It gets in the way, and more so when all you want to do is to tweak a CSS stylesheet. And I haven't even mentioned how hard it has become to change the DTD and then recompile it and import it into your project.
And I won't, because my blood pressure is important to me.
So while XMetaL in its latest reincarnation is very nice, I still consider version 3.1 to be superior for a number of reasons, of which one important one (to me) is that I can run it in and wine and Linux.