At first I disagree that "Reiter" for "Tabs" is borderline. It's a lot below the belt! I've got a task where "Reiter" was mentioned and long I have no idea what's going about in that task because the only translation that, for example, Google Translator gives, is 'rider' or 'horseman' :)
It strongly depends on what environment you're working in. If you're working in pure German environment, it's probably OK to translate everything possible, as long everyone understands... But when you're going internation, or considering doing so in the future, you should keep at least the terminology in English.
In my opinion, German translations of IT terms are too hermetic, they are simply not understood by people from outside, even if they have quite a good German skills (the infamous Reiter attacking).
Additionally, try to find help to change some settings of Windows or Firefox, if you're using German version. The solutions are mostly in English, and you have to think hardly, how how could that option be called in German to apply such solution...
From my experience, people tend to translate everything, including "inheritance". But then they have tremendous problems using English documentation and stick to German translations only. It's your choice, anyway. Just be aware of consequences.