Hi Stephane,
Thank you for your update.
I am not sure of what be might be causing this strange behavior without a working sample. I have tested this issue in the attached sample with Essentail studio V.4.x/5.x. But i was not able to reproduce the issue. Is it possible for you to upload us a minimal sample or modify the browser sample to reproduce the issue here? This will help us to analyse the issue further.
Sample :
ModifiedFilterBarDisplayMember.zipThanks for using Syncfusion product.
Best regards,
Haneef