\input{}, \include{} and \includegraphics{} and maybe some more.However, commands defined by extra packages (e.g. subfiles) are ignored. This is not a surprise, as TexnicCenter cannot know all possible tex-commands, but maybe some option could be introduced in TexnicCenter to extend the commands for recursive scanning of the files list.
I would even suggest to make this a project-specific option (within the tcp file) but I would also be happy to see that feature in the main options of TC. Then people could add i.e.
\subfile{} to the list and subfiles and its child files (i.e. figures) would also appear in the files list.(disclaimer: I have looked around for quite a long time and did not found a solution for that yet. If there is an existing solution for that, I apologize)
