Hello Luc,
Thank for writing.
I tested described issue with version 2013.1.220 but I was not able to reproduce the described behavior at my side. You can find attached the sample demo project that I used during my tests. Could you please take a look at it and modify it in a way to replicate the undesired behavior? This will allow me to investigate it and provide you with further support.
Thank you in advance for your cooperation. I am looking forward to your reply.
Kind regards,
Anton
the Telerik team