Comment # 2 on bug 1158074 from Ricardo Gabriel Berlasso

(In reply to Tom���� Chv��tal from comment #1)
> If I am not mistaken the
> additional option is based on language tool extension that is just bundled
> with the upstream release:

No, LanguageTool is not bundled with LibreOffice: if you install the extension,
you get new menu entries under Tools menu, not under Options. LibreOffice's
built-in grammar checker is based in LightProof and was added in 3.5

https://wiki.documentfoundation.org/ReleaseNotes/3.5

Problem is that Leap's LibreOffice still does some grammar checking for English
documents, but you cannot configure it. Try this: with a clean user profile,
without extensions, set a document to use the English language and type

    there is a problem . Here.

The "there" at the beginning of the line and the first dot will be underlined
in blue. That's not something detected by the spell checker, it's the grammar
checker at work, but you cannot configure it in Leap's LibreOffice.