F12 no longer works in Visual Studio

Question

This is driving me crazy. Ever since I installed ReSharper 4, F12 no longer seems to work. If you look at the all the ReSharper short cuts in the Goto sub menu Declar

Answer 1

For ReSharper Ultimate 2017.3.3 and Visual Studio 2017: Tools > Options > Tools > External Sources > Default Visual Studio Navigation > Save