When using certain interactive blocks such as the Stonecutter, Loom, and Enchanting Table, side mouse buttons can still trigger selection actions despite not being bound to any in-game functions.
Linked issues
relates to 3
MC-297624
The stonecutter UI buttons are not keyboard-navigable, preventing the player from refilling the input by pressing the spacebar
Open
MC-298546
The loom UI buttons are not keyboard navigable, preventing the player from refilling the inputs by pressing the spacebar
Open
MC-298547
The enchanting table UI buttons are not keyboard-navigable
Open
Can confirm, any button from Mouse 1 through Mouse 5 can select a block in these GUIs.