Visual Studio 2015 XAML files freezing

Question

I've recently updated the version of VS from 2013 to 2015. I work on WPF and obviously, I have to modify *.xaml files; every time I leave a .xaml file Visual Studio freezes for about 15-20 seconds. I cannot work like that! I've uninstalled Reshaper, but no change. I've closed even the designer process, but still - no success.

When I try to run VS without administrative rights it freezes even more (about 30 seconds). If I try to open the same solution with VS2013 it works very well.

Station details: 12 GB RAM, i7 2.5GHz, SSD, Windows 10 x64

Does anyone face the same problem? How to solve it?!