Finally I got around to trying this. But I cannot reproduce the problem.
I took the file put it a project and searched for some text snippets with Cyrillics and it works for me.
My guess is that this is probably a platform / locale specific problem. Somewhere there are probably some calls in the code that aren't passing the 'encoding' to some of the Java file and io apis. But in my environment the default encoding is probably UTF-8 and so things work out for me.
Probably if you are hitting the bug your default encoding ends up something else and the problem arises.
This is really a bug that should be fixed... but maybe there's a workaround for now... can you please try adding:
to your eclipse.ini file?