Code coverage tab did not show

We run .Net tests using NUnit via supported tasks of MSBuild(use .proj file), according to 

https://confluence.jetbrains.com/display/TCD9/Configuring+.NET+Code+Coverage

if I turn on the code coverage using JetBrains dotCover, the code coverage tab should automatically show up. However I did not see any code coverage information at all.

Also I saw the warning information below the combo box. Is this warning message telling me that the code coverage only works for the Teamcity NUnit runner? I am confused. Could somebody please help me?

thanks

Xiali