How does inventory work with BTO items?

For exampe:

Add a BTO product "T-Shirt" with 5 options (Colors).
You have 5 T-Shirts, each with a different color.
So, set the inventory for the BTO product to 5.
Then, create 5 BTO items, one to represent each t-shirt color.
Set the stock of each of the 5 colors to 1.

That way, there are 5 total shirts in stock, with one of each color being in stock.

The problem I'm having is that the BTO items who's stock is set to zero (who are out of stock) are still displaying as a BTO option, and nothing is being shown to the customer to reflect that this particular BTO item is out of stock.

I tested this by changing the BTO Item's stock to 0 manually. Is there some other process which takes place when an item is actually bought that marks it as being out of stock?

I had assumed that, once the stock of that particular BTO item dropped to 0, it would no longer show up as an option for the BTO product (or for any BTO product it is assigned to, for that matter).

Turns out i needed to change this setting under BTO Settings:

Should your store's general inventory settings apply to BTO Products? Yes - Use the Store Settings area of the Control Panel to edit general inventory settings for the store. No - BTO products are always available for sale, regardless of general inventory settings.

Had to change that to yes. I didn't realize it applied to BTO items as well, but it makes sense now.

T-Shirts is just an example everyone can relate to ;) thanks for the tip though