The category menu could be much more friendly for navigating a category/subcategory structure, from both a performance and behavior point of view.

Every click in the category structure appears to trigger a completely new screen, and a significant delay before the screen refreshes with the new view. Potential customers are quickly frustrated by delays like this.

There is no visual cue where the user has clicked, i.e. the category/subcategory node is not highlighted. And a click through to product detail or an add to cart doesn't maintain location in the category hierarchy. Returning to the products page is a return to the original unfiltered, unselected list.

If the list is not presented expanded, and a user expands a category, that expansion is lost upon return from cart or detail.

These observations are in addition to the earlier post about the error when a product is deleted, wiping out subcategory values for all other products in the same subcategory. These observations are annoying; the lost subcategories error is major.

Here's a suggestion to reduce the impact of the category navigation performance...

Give us a configuration option to set the default number of items displayed (current default appears to be 10). I tell people to set the number to 100 (max available), and then they can scroll the entire list of products without having the refresh delay, and it helps the customer that wants to browse everything. It would also help when browsing a category/subcategory with more than 10 items.