Megamenu caption with accentuated chars int T3 v2.5.2 => Template returns to default params

Problem is persistant in T3 2.5.2 / Joomla 3.4.8



Create a Megamenu caption with accentuated char => This works fine
Edit any menu item with joomla admin (just open/save)
Template returns to defaults



What happens :
In the database, template parameters field is altered because all accentuated chars are escaped by a "\" when the mm_config_needupdate flag is added => field is now unreadable/unparsable =>default parameters are used.

I did not try with apostrophe which might also cause trouble.

This makes one of the superb features of T3 unusable in many countries/languages