jQuery Grid Plugin - jqGrid

I am using jqGrid 4.5.4 for ASP.NET MVC application in which I have an issue with column separator.

First grid is the one I am using, when I am trying to expand the column using column separator at pkd column I see the separator line is showing away (in between create date column)as seen in image.

I am having this behavior across all the columns (Column Separator line displays away) through out the jqGrid

Second grid is from the demo in which I clicked on CustomerID and I see the column separator exactly at the end of CustomerID column