Add exising items does not automatically add to subversion repository

I had the problem, that I added files: foo.h and foo.cpp to a project that is under subversion control.
The editor added the files to the .pro file correctly but did not add the files to the subversion (there was no question during the adding to add the files to subversion, too)

The subversion menu also did not offer to add the files, when selected in the Project-Panel.

What I did before:

I opened bar.h and bar.cpp of the projects (both under version control) and saved them as foo.h and foo.cpp. They were still in the editor, but not in the .pro file. So I asked to add these (now) existing file (foo.h, foo.bar).

Maybe this procedere was confusing a kind of subversion controlled files cache ... ?

Restarting QtCreator helped.