Minecraft version
1.16.2

Mod version and malilib version
0.0.0-dev.20200824.031346

Description of the bug
When using pick-block on the ghost blocks in the schematic, and the block is not already present on the hotbar, then Litematica doesn't move the block into the hotbar according to the logic of the vanilla pick-block. In vanilla, pick-block prioritises first empty slots, then the selected slot, but will avoid replacing items like tools or food. In Litematica, however, it cycles through hotbar slots every time a new block is moved into the hotbar, replacing them regardless of what was already in them.

I think I have already changed this behavior somewhat in the later development code in 1.12.2, but yes it will still probably need some changes and improvements to how it works.