Break lines in form#buy_block

[MaJoran243]

Hi,
I've a question relating to the customization of the buy block when displying an article. I have several attributes (color, size, etc.) which are shown in the product view. Unfortunately the selection field isn't broken to the next line after the label name is shown and so it looks a bit weired. I searched almost every file in my template and all prestashop folders but I can't find the file which layouts the attributes. Maybe it gets more clear by viewing my screen shot. Maybe someone could help me solving this issue.
Thanks for your help