Switching to ES2 preview recompiles shaders every time - how do I fix that ?

My project is for mobile/VR platform, which requires me to check how things look with ES2 renderer. When I switch to ES2, shaders get compiled and it takes forever. It happens every single time I open the project.

Is there a way to have this done once and then afterward never have to worry about shaders being recompiled? (unless they really need to be recompiled)

Thanks

bumpy bump