Thank you for writing.
RadPropertyGrid uses the CurrentUICulture to convert different data types to a string representation. This though is not the correct way for the job. It should use CurrentCulture. I have logged this issue in our Public Issue Tracking System - PITS
. You can track its progress, subscribe for status changes and add your vote/comment on the following link - PITS Issue.
Until the issue is resolved you can workaround it by setting the CurrentUICulture of your application explicitly.
I have also updated your Telerik points for bringing this issue to our attention.
I hope this will be useful. Should you have further questions, I would be glad to help.
All the best,
the Telerik team