Thanks for testing this, tomsem
. I was considering getting a Fire, because I was hoping that they might have fixed the dictionary limitations along with KF8 support. Apparently this is not the case, which is a pity since Mobipocket Reader had none of these limitations.
Unfortunately, none of the Kindle homebrew developers seems to be into languages. I had hoped that by now someone would have hacked the dictionary lookup code or ported StarDict or another dictionary client for use with .mobi files.
But so far there's only Duokan whose StarDict client is extremely limited und buggy.