Is the vulkan editor supposed to be working (I know its experimental) in 2018.2 b2? I have ticked vulkan editor support in player settings and restarted but it still seems to be OpenGL.
Did you also make Vulkan the first choice in the graphics API list for the selected build target? (If you're building for standalone, you need to uncheck Auto Graphics API for Linux for the list to show.)
Seemed to be an unrelated driver issue despite Vulkan showing it's functioning correctly. It works now. If anyone has problems on older gen (Haswell for me) Intel graphics try reinstalling your drivers. Also make sure DRI3 is enabled in your xorg conf. You can check by going to /var/log/Xorg.0.log and seeing if "DRI3" appears in the log.
I had the same problem as gegs97. And then I realized I have never updated my drivers. Works great now!