Auto stacking with stackable items

Please make it so that if for instance I have 20 metal in a stack in my backpack, and I add another stack of 20 metal, it joins into that stack to create a stack of 40 metal instead of having two separate stacks of 20 metal each. This is especially annoying when it comes to the construction pouch, where there are only three slots, so you often need to waste time manually adding materials to the stacks already present in the pouch rather than just depositing it inside.