Designer Crushed
With latest version xaml designer is crushing. In App.xaml
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="ms-appx:///Intense/Themes/Intense.xaml" />
</ResourceDictionary.MergedDictionaries>
``` this xaml file is not found and in Shell.xaml
`Background="{ThemeResource SystemChromeLowColor}"` SystemChromeLowColor this resource is not found, I am using visual studio 2015 update 1
Are you sure the Intense nuget package is correctly referenced in your project?
I'm not seeing this error in VS 14.0.24720.0 D14REL, I get the expected message "App.xaml cannot be edited in the Design view."
Please refer to the screenshots. I have downloaded the latest version of Intense toolkit and my visual studio version is the same as yours.

Have you attempted to compile your project?
Yep, but no luck, though the project is running successfully on emulator but designer is not available like you can see in the previous images
Have exactly the same issue with a fresh Nuget install. I had to copy and paste in the themes folder from GitHub "intense/0/Libraries/Intense/Themes/" and reference that.
Having the Same Issue... It's a VB project - based on the SplitViewApp template - if that helps...