Hi Hassan,
Thank you for posting your query to us.
I am afraid that I am not able to reproduce the issue mentioned here. Also I have created a sample to test this issue and it is available in the following link:
http://websamples.syncfusion.com/samples/Grid.Web/6.1.0.34/41631Video/41631.zipPlease have a look at the above sample and if still the issue exists, could you please try reproducing it in the above sample and send us the modified sample so that we could sort out the cause of the issue and provide you a solution?
Regards,
Janagan.