Application menu always in English

Strangely the language of the applications menu which appears, when you left-click on the desktop, is always in English (not the appication names, though), no matter what you set the system language to. Is this a bug?
I have found that I can edit ~/.e16/menus/ After the edit, it appears immediately as edited. The changes are not permanent alas. They obviously are overwritten after Logout/Login or after Reboot, and the menu is in English again. Is there a mechanism in the background which can be changed by the user to prevent overwriting the changes? There probably is some script which does this, and which runs every time at startup or login, I assume.