I cannot get to work code autocompletion in Clion.

I have followed this guide (http://docs.platformio.org/en/latest/ide/clion.html) and installed PIO Core, then I have created a new blink project. I have managed it to work from command line.
(Just created a main.cpp with "blink" content and executed pio run -t upload. It works nice).

However I need autocompletion in CLion. I have added a line
add_executable(myproject src/main.cpp)
into CMakeLists.txt, but i doesn't help.