ng-grid row position changed in grouping when used cell template

I have tried to add grouping capability to ng-grid and its working fine.But the problem was that when i expand group row(arrow icon)it will mess css styles and there was a lot of gap between arrow icon and row content .so it will waste lot of spaces.i have tried to overcome that problem but couldn't find any solution.please let me know how to solve this.

(Note:I have figured it out gap = rowHeight in gridOptions.because i have set height for grid)

$scope.gridOptions = { data: 'restData', rowHeight: 245, enablePinning: true, columnDefs: [{ field: 'testPlan', displayName: '', cellTemplate: template }

here is my working example http://plnkr.co/edit/zaeyxANdyPPevUaggBTj?p=preview

Any ideas what went wrong.Thanks.