I've tried using windowClick with no success. Maybe I'm doing something wrong?
ItemStack rst = mc.player.inventory.mainInventory.get(8);
int potpos = itemStackPos(potst);
ItemStack pot = mc.player.inventory.mainInventory.get(potpos);
mc.playerController.windowClick(mc.player.inventoryContainer.windowId, 8, 0, ClickType.PICKUP, mc.player);
mc.playerController.windowClick(mc.player.inventoryContainer.windowId, potpos, 0, ClickType.SWAP, mc.player);
mc.playerController.windowClick(mc.player.inventoryContainer.windowId, 8, 0, ClickType.PICKUP, mc.player);