# Eclipse with texclipse code completion

I am using Eclipse with texclipse. Code completions are not showing up for some of the commands. For example: \mbox{}, \mathcal{} and for some others that i cannot recall at the moment.

(If this single command does not suffice for answering why it doesn't show up in code completition let me know, then i will do thorough search of those commands.)

How is it possible to make specific commands availible in code completition?