Can we get the targetframework switching described in http://stackoverflow.com/questions/12041290/monodevelop-is-it-possible-to-switch-pcls-compiler/12062589#12062589 automated at build time using MonoDevelop?
I realise this comment in the StackOverflow answer says "this is fixed in Mono 2.12" but I'm not sure this includes the tool support. (Sorry if I've completely mis-described this problem!)
It was fixed in https://github.com/mono/mono/commit/f415e91c696620a9f69fc1fa7017a66a9a25ee3d
*** This bug has been marked as a duplicate of bug 6649 ***