Can't drop item while a GUI is open and there is an item in the cursor

When in the inventory you can always drop items, including when already holding another item in the cursor, but once a GUI is open you can't drop an item while holding an item. This is clearly unintended and inconsistent, as the cursor dropping behavior changes depending on what GUIs are opened besides inventory.

Steps to reproduce:

1. Open the inventory

2. Take an item into the cursor

3. Hover over a different item and press Q

4. Observe that the item is dropped

5. Place any block that opens a GUI, e.g. crafting table

6. Open the GUI, e.g. of the crafting table

7. Select an item

8. Hover over a different item

9. Try dropping the item

Observed behavior:

Observe that despite not using the crafting table and being in the same inventory as before, the item isn't dropped

Expected behavior:

Item drop behavior should be the same no matter what additional GUI components are opened