Hi Geza,
Thank you for your interest in Syncfusion products.
We were unable to reproduce the reported issue with "column width and inline editing",so could you please try to reproducing it in the below sample and send us the modified sample so that we could sort out the cause of the issue and provide you a solution?
We have created the sample in our latest version 9.104.0.20.Could you please inform the version which you are using currently so that we could provide you a solution accordingly.
Please find the sample from attachment.
Note:If you want to run the sample in MVC3, change the configuration manager as Debug_MVC3/Release_MVC3.To briefly know about switching (Mvc2 to Mvc3) steps, kindly refer this document link.
How to Switch between MVC2 to MVC3Please let us know if you need further assistance.
Regards,
Eswari.S
Grid Editing_fbf687c6.zip