Company doesn't suggest candidates from TAGS

[Andrey Lisin <andrey.lisin@gmail.com>]

Hello,

I'm new to company-mode and have one question (haven't found anything in
documentation).

Here is my use-case. I have C project and use etags to navigate through
it. `company-backends' variable is

(company-bbdb company-nxml company-css company-eclim company-semantic
company-clang company-xcode company-ropemacs company-cmake company-capf
(company-dabbrev-code company-gtags company-etags company-keywords)
company-oddmuse ...)

I have `foobar' variable defined in header file. Now I edit c-file and
start typing `foo'. I expect to see possible complition `foobar', but
nothing happens. But if I run `company-etags' command I see `foobar' in
completions list.

My question is how to make Company to show me etags suggestions by
default, e.g. by company-complete command?

Thank you.