Currently, the game inventory is set up so that if your inventory is full, and you have an item in your hands that’s not in a tool slot, you’ll drop it if you switch to something that doesn’t free up an inventory space.
I feel like adding in a way to prevent swapping non-toolbelt items out for a toolbelt item while having a full inventory would help a lot of people. This would involve an error message saying something along the lines of “My bag is full. Grabbing that would risk losing something.” for items that won’t free an inventory space for the held item.
If we could have something that prevents accidental item dropping, I’m sure that would help many people out.