jquery ui - how to make sort icons visible in all column headers in jqgrid regardless on sort status

Question

jqGrid column shows sort icons only if column is sorted.

How to make sort icons to visible in all columns so that user has idea that sort can be performed clicking in column header? Probably both sort direction triangles must be in inactive.

Telerik radgrid has this:

http://www.telerik.com/community/forums/aspnet/grid/possible-to-show-sort-icon-regardless-sort-status.aspx

How to implement this in jqGrid ? Currently there are no any indicaton that columns are sortable.

Update

I tried solution from answer using colmodel below.

Issues:

1. For narrow and columns sort icons are not displayed or displayed partially. There is wide empty space in right side of columns header. How to decrease this empty space so that column header text and sort icon can appear in this area?

2. After sorting, sort icons in all columns except sorted one are lost. How to persist them ?

Answer 1

viewsortcols : [true,'vertical',true]