When I add the localization string for the hover title of close button at the top of the net chart node menu (not the one in the menu), it only works if I add it when creating the chart. It does not seem to work when changing it through updateSettings like the rest of the translations seem to work.
We have the ability for the user to change the language on the fly and I was trying to not have to tear down and re-create the chart.
Please see a fiddle forked from your gallery page. If you uncomment the localization in the chart creation it works fine.
http://jsfiddle.net/5xxanLxr/