Related to a Hunspell 1.3 bug (missing morphological analysis of compound words: http://sourceforge.net/tracker/?func=detail&atid=756395&aid=3544994&group_id=143754), some optional features of the Hungarian grammar checker (eg. "Underline all generated compound words") don't work in LibreOffice.
Fixed in Hunspell CVS, also in a LibreOffice patch (tested by the morphological analysis of 1.8 million Hungarian words). Test in LibreOffice: Choose Settings of Extension Manager -> Hungarian dictionary extension, and set "Underline all generated compound words" option. The word "macskakutya" in a Hungarian document will be underlined by blue wavy line.
Laszlo Nemeth committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=88303a8303d35dd927c051811af869568dd7c838 fdo#55045 fix broken Hungarian grammar checking options The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.