Larian Studios Forums Divinity - Original Sin Divinity Original Sin - Help/Tips/Tricks Potion of Courage.. how?

So this might be a really stupid question but I know it takes

Pumpkin+Apple+Empty Vial

However I can't seem to combine the ingredients and can only use one or the other.... how do I make it so I can combine 2 ingredients?

You need no empty vial for the potion. But I don't think you could use the potion anyway. It's only used for a quest with Frederick.

How do you combine the two items?

You drag one on top of the other.

you can kill frederick, and you won't have need of any potion for the imp's freedom