Open LibreOffice 4.2 beta2, localized. Tree items under Tools - Options - LibreOfficeDev are not localized. In cui/source/options/treeopt.src there are 16 elements in ItemList. In po files there are 17 (mostly), because Expert Config was not removed. I tested --with-langs=en-US hu sl. hu had 17 elements, sl had 16. In workdir/SrsPartMergeTarget/cui/source/options/treeopt.src this tree was not localized (even not in Slovenian, which matched!). Then I tested --with-lang=en-US sl. In workdir/SrsPartMergeTarget/cui/source/options/treeopt.src this tree was localized in Slovenian -- good.
Fixed in master.