[1.7.10] How would I check which slot a mouse clicked?

[starwarsmace]

So I need to see which slot a mouse clicked in the inventory. So what I tried was getting the slot display x or y and comparing it to the mouse x or y. I thought it would work but the numbers were really random. And I couldnt find a good way to check. So is there some function that I can call in guiInventory to get whether a slot was clicked? Also, Im checking whether it is a middle click.

[coolAlias]

Extend GuiContainer - you then have the handleMouseClick method which has the Slot and slot number as the first two parameters.