Multiple categories for each product

Thanks for a very useful shopping cart, I have a small problem though...

Lets say I have three categories;

• Fruit
• Vegetables
• Herbs

When I create a new product, i.e. "Banana", I want it to appear in both Fruit and Herbs but the select-object doesn't work like that. I can select more than one categories for my product but only the ones next to each other, like Fruit and Vegetables.

I've tried this in several browsers on both mac and pc but I get the same problem.

Is there anyway to work around this? Any help would be greatly appreciated!

CTRL + click should work