First: There is similar but different bug already in Github.
OS: Windows 7 SP 1 x64 German locale
Ctrl++ on NUM block works.
Ctrl+ - on NUM block works.
Ctrl+0 on NUM block does not work.
Ctrl+0 on standard keyboard works.
So the problem here is that Ctrl+0 pressed on the NUM block does not work but pressed on the standard keyboard does work. Obviously a minor bug but nevertheless something that can probably be fixed.