HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

Unfortunately, this option won't work. Baratorch says that for some reason, he can't implement it. Apparently, the VT scripts are interfering. It's a pity, of course :(

And what else is new besides splitting the stack in half? It wouldn't be difficult to do in VT, but there, Shift+click has its own functionality: combining with a similar stack instead of swapping slots in the hero's status window. And the standard functionality in other windows is also useful.