Users have error when saving modifications

Hi,

Users on a website tell me they have error when they are saving modifications on every document :



The point is the modifications are saved !

Where this error comes from and how to remove it ?

has this behaviour been there from the start or did it just start?
does it happen for every user, or just for a specific usergroup?
which version of MODX are you using?
do you have custom ACL's?
did you try to empty the cache remove everything from core/cache?
did you try to reinstall modx?

RDG