Hi,
I have setup the environment with VS2012, VS update3 and phone SDK, but cannot repro the problem you reported.
From your pre-description that you failed to install the VS updates, we think that your VS environment may be messed up by some reason. So we will suggest you repair your VS
and then install the VS Update3 from “工具 ->
扩展和更新 ->
产品更新”.
Please let me know if you still have this problem after that.
Thanks,
Lingling
Lingling Tong - XAML Design Tools