It happens only when Preferences selected to French. The selector front/back is grayed out.
Mac OSX Server 10.7.5 with MAMP Pro.
Hey Gautier, could you look at this?
This is fixed since the end of january in github source. Sorry to report this several months after, we exchanged with Manuel on this by email.
My JIRA account was setup with an email address I wasn't checking, I missed all notifications. Corrected now.