dynamic colModel dataModel causes clicking col to not sort

[gilem]

If I create a grid with a custom colModel, and then click a column, the sort does not happen.  Interestingly, if you click a column to sort, and then change the number per page, the sort column shows displayed, but still does not sort. sorting is set to 'local'

[paramvir]

Could you please share your implementation in jsfiddle so that the issue could be seen.

http://jsfiddle.net/b6b710mz/9/