Did you mean to title the thread, 'VS2015 include header from VS2013'?
Normally, I would ask you to try clicking 'Rebuild' and 'Clear' in the following menu. (VAssistX | Visual Assist Options | Performance)
Then, restart your IDE.
However, since the issue still remains, try typing out the correct include like '#include <future>'. Then, delete the include and try to add the include through Add #include Directive. This could help ensure Visual Assist knows about the correct file.
Sorry - yes - fixed the thread title :D I did exactly that - typed the corrected one and intellisense / VA seem to seeing the correct thing. I'll post here if I get anymore of this same behavior.
I believe this is due to case=65910. It is fixed on our main line, but the fix did not go to the release branch for 2114. We'll try to get it on the release branch for next month.
Sorry -- this did not get fixed in build 2116. The fix that we had did make it to the release branch -- but testing failed. We'll revisit it and contact you once we have test dll.