Broken Select2 Menus – WooCommerce conflict

Hi,

I had written some code to place a Select2 option menu in a custom meta boxes in my post edit page (admin). And they were working when I wrote the code. Tonight I noticed that the menus were broken (the code was producing completely incorrect HTML). During my investigation (by deactivating plugins) I noticed that when WooCommerce was deactivated the menus appeared correctly.

I am still using 2.6.14 – do you know what might have changed recently (up till 2.6.14) that would have broken my basic Select2 code?

Cheers