Cannot Build a project of simulator after changing the lv_ex_conf_templ.h file

I am building the simulator project on a PC with Windows 10 and CodeBlocks, following the instructions on this github page: Everything works fine and I got the build project running successfully.

However, when I was trying to change the lv_ex_conf_templ.h into lv_ex_conf.h, as instructed on this page:, the rebuild failed at line 71 in the main.c file, the demo_create() function. Anybody know how to fix this problem?

You also need to enable the apps you want in lv_ex_conf.h. Did you do that?

After changing the LV_USE_DEMO from 0 to 1 in the file lv_ex_conf_templ.h, I can successfully rebulid the project. Thank you.