NG-Grid过滤器不能正常工作

I have a really basic grid using Angular.js and NG-GRID with the showFilter: set to true. However if I search for the value in the Marketing Start Date Column, 200101011. It doesn't show. Actually as soon as I start typing a 2 in the filter text it should find all four records, but only 2 show up.... Here's the Plnkr I have a really basic grid using Angular.js and