Most visual elements in a graph can be reordered using the Customize option from the right-click menu:
![7176_ContourGridCustomize.png 7176_ContourGridCustomize.png](https://community.jmp.com/t5/image/serverpage/image-id/780iF3903029F9B97D29/image-size/medium?v=v2&px=400)
From the Customize dialog, select the Grid Lines object and use the down-arrow button to position it below the Contour object (which sounds counterintuitive - this list is the order in which objects are drawn):
![7177_ContourGridReorder.png 7177_ContourGridReorder.png](https://community.jmp.com/t5/image/serverpage/image-id/781i5BEFDBCF3E0850C0/image-size/medium?v=v2&px=400)
Result:
![7181_ContourGridOver.png 7181_ContourGridOver.png](https://community.jmp.com/t5/image/serverpage/image-id/782i95C01F8EB3B03A8D/image-size/medium?v=v2&px=400)
Hope that helps!