Summary:
Pick block is used 1 time if the pick block button is on the mouse. When assigning a button on the keyboard, the pick block will be used continuously when held down.

Steps to reproduce:

1. Assign a pick block to a keyboard button.
2. Hold down the assigned button in the game.
3. Aim at different blocks.
4. Assign a pick block to a mouse button.
5. Hold down the assigned button in the game.
6. Aim at different blocks.

Observed results:
Pick block is used 1 time if the pick block button is on the mouse.

Expected results:
Pick block is used continuously while holding down the key.