Unable To Move Blocks in Inventory by Clicking Mouse

What I expected to happen was...:
While in my inventory I would be able to move an object (ex. sand) by clicking on the object

What actually happened was...:
Instead, The block wouldn't attach to the mouse icon and move with it (it would stay in the slot) even if I clicked on a different slot it wouldn't move

Steps to Reproduce:
1. Go into inventory
2. Click on an object
3. Notice the object doesn't move