This extension for OpenCart allows you to manage category and product from same screen. Using this extension you can view, add, edit, copy, delete product to specific category. You can also add, edit category as well as add sub category from same screen using this extension. This extension uses vqmod and ajax. No file is replaced but you need vqmod to be installed though.
For full demo please visit http://psskhal.com/demo/admin
UserName: demo Password: demo
After login goto Catalog > PCategories