Additional fields (for size i.e.) seems doesn't work properly

[testJL]

Hi,

I was trying to add new product (T-shirt) with additional field "size" and 3 options to choose: M, L, XL (required).

Next I set quantity: 5 for each size.

Next I set overall quantity for the product: 15 (it doesn't set automatically).

Everything looked OK, so then I made test: I added to cart 6 T-shirts (size M), and it worked. But I don't understand why? It should alert a customer, that there are only 5 T-shirts size M.

Could you please find out if your demo store works properly?
http://www.smfhacks.com/storedemo/index.php?action=store;sa=view;id=12

If so, than what did I make wrong?

Edit:
I use SMF Store 2.5 beta 1 (updating to 2.5.5 doesn't fix the problem) and SMF 2.0.9

[SMFHacks]

So it is just the qty for a select field issue right if you go over the limit?

[testJL]

When t-shirt doesn't have additional fields for a size - everything works properly.

When t-shirt does have sizes - customer could add to cart as many M size t-shirts as the number of all t-shirts (M + L + XL).

Moreover, customer could add it to cart several times (i.e. there is 5x M size, 5x L and 5x XL, 15 t-shirts total, so customer could add 15 M size t-shirts to cart for the first attempt, then go back to store and add another 15 M size t-shirts, etc.)

[testJL]

Anything?

[SMFHacks]

Haven't had time to look into it.