Hi Driss,
There were some issues with using the Grid in a MasterPages in version 4.1.0.50. We have already addressed these issues and a patch version has been released
Essential Studio 4.1.0.62 download link
More details of this patch
See this forum
We appreciate your interest in Syncfusion products.
Sorry for the inconvenience and thank you for your cooperation on this issue.
Thanks,
A.Sivakumar