How to customize Products list in "Add App" page?

[#1]

Hi,

My requirement is, in the "Add App" page, to add side bar to the hierarchical view of products. If I see the source of the this page, the div class="form-item" is used for the product list and a different id is used for each product. I wanted to use same id for all products and add styling for product list. But I could not find the location of the class in the code. Can anybody points me, where it is defined in the code?

Thanks

Swarna