Welcome to tatoeba :)
In fact they're not linked, that's why the arrow is in grey :)
http://tatoeba.org/eng/faq there's a quick explanation here
and you can find a much detailled one here
http://blog.tatoeba.org/2010/02...n-tatoeba.html
Of course, if there's still something unclear, feel free to ask me, or on the wall section :)

Thanks =)
Sorry, I don't mean to be presumptuous since I'm new, but shouldn't there be a way to remove it when it's clear the translation is incorrect for the main sentence, even if it is indirect?

No problem, don't hesitate to propose suggestion, we're human after all, so we may have missed things, even obvious.

In fact here the problem is time ^^ We're 2 main people taking care of the "coding part of tatoeba, and it's a bit small compare to all the things we could implement in Tatoeba to make it perfects :)
The issuse has already been discussed (note that I still didn't have found time yet to implement a search feature on the wall , sigh:( ), for the moment the limitation come from the fact the current architecture we've made does not handle the possibility to qualify link, so all links between sentences are assumed to be "is a translation of" link, because anyway what you've said internally would be an explicit "is not a translation of".
But rather than not displaying it, maybe will it be better to display it but with a red cross something like that, to clearly show it's not a correct translation. Because I think it's valuable to know how to translate a sentence, but also how to not translate it, as most of the "not a translation" are in fact quite close to the "good translation" (here for example the 2 english sentences differ from only 1 words), it's good to know that one is correct and one is not.

As you new, I think you don't know, but we're currently preparing a major new version of the website, change of the architecture etc. and one of the feature will be this, it's planned, though I don't know yet when it will be here.

Actually, the problem is with the Italian sentence (it says "they usually sleep in this room"). If we unlink it with this sentence, the wrong indirect link will be gone. ^^