It's a single product, composed of multiple projects/targets building different dlls/executables. That was my understanding of the point of a "solution" (vs the old days of VC6 when there were only projects and workspaces). Anyway, it used to work back in the days when most of Chrome's code came from WebKit. Now we're many times bigger. It's clear MSVS' project UI is not intended for building projects of this scale. I'm assuming Microsoft doesn't use this UI to develop windows, or office, so it's not surprising this case isn't supported.
I have no idea what the Windows or Office people do, but the Visual Studio group certainly does build their own software in VS. (Or did as of mid 2009 when I quit, anyway.) It was not a particularly pleasant experience!
