Hi Mary,
Sorry for the inconvenience caused.
We are able to reproduce the issue. while setting ColumnSizer as SizeToHeader default column width is applied to the GridDataVisibleColumn. But all the other ColumnSizer(SizeToCells,Star,Auto etc) are working fine.
Please created the incident in Direct Trac, so that you will provide the fix this issue.
For your reference, please find the tested sample below,
Sample:<
http://www.syncfusion.com/uploads/redirect.aspx?&team=support&file=CS-1825171668.zip >
Please let us know if you have any queries.
Thanks,
Rajasekar