If using the Apple Magic Mouse (which has no physical buttons), scrolling now causes the view of the player to be altered in addition to scrolling through items. I don't have another mouse to try, and I have been using this mouse efficiently with Minecraft for Mac ever since release.
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kumasasa
Duplicate of MC-15705, please use the search function to see if your bug has already been submitted. Currently over 56% of tickets are being closed as duplicate.