I hope this wasn't reported already

1. Perform this command

   /scoreboard objectives add Inventory dummy
   

2. Then perform this command

   /scoreboard objectives setdisplay sidebar Inventory
   

3. Build a clock which runs this command:

   /scoreboard players add @a Inventory 1 {Inventory:[{id:minecraft:stone}]}
   

4. Put a stone in your inventory, the score should increase, now take it with the cursor to move it

The score stopped increasing

Now even if you say this is a feature request or no bug, it is as the "/clear" command can clear this "slot".