I think i understand some of the confusion here. I dont have the category menu and product detail on the same page.
I wanted to have a navigation page with a grid of big category images that drills down and seperate a product list/detail page.
Whilst your solution would probably work if both category and list/detail modules are on one page but it wont work if they are on seperate pages.
I say this because there is only one place to put a tab id in for the list tab.
If you set the product list tabid as the same page as the category tab then you get drill down working, but if you do that you dont get listings/detail as the category links all point to the category tab.
Alternativly if you put in the tabid of the list/detail page then you get links to the correct category on the product list page but dont get drill in anymore as all category links to to the list page.
Its one or the other as best i can tell. Anyway, in short i have given up on this, i have no doubt it can be done by changing the source so perhaps ill look into that at some other point but for now ill have to go without.
If you are working on the category menu and feel like adding this feature by all means send me a beta and ill test and provide feedback for you.