When I press and hold the mouse button outside the buttons (Pic-1), move the cursor onto the button (Pic-2), and then release the mouse button, the item page changes (Pic-3). This means you don't need to click on the buttons.

This feature has existed for a long time (even in Minecraft 1.8.9), so I don't know if this need to be repaired.

(Using translation tools so there may be mistakes in grammar XD)