For example, when adding SDL library and writing the beginning of the name of SDL_... function in Windows, possible functions list appears on the screen.
Just to let you know, I have noticed the same behavior on my
GNU / Debian testing machine and for some reason autocompletion does not parse properly. I'm compiling C::B myself always with the latest revision and indeed there are moments where I get really irritated by the mechanism with how it "forces" me to reparse the entire project.
Nevertheless, it's a minor issue as it parses the project on the background which eventually makes it possible to use again autocompletion. Usually I safe the project, then press
Ctrl+F11 to rebuild the project, run it, and then check the autocompletion mechanism. After all this fuss, it works normally.