The bug is triggered no matter what game mode I am in. When 1.5 came out on my MacBook I was no longer able to just click an item to pick it up, I had to drag it. Which is very annoying when you are in a hunger games server for example and you need to get out quick. I have no idea how the bug triggered, it just did.
418th Duplicate of MC-5130, please use the search function to see if your bug has already been submitted. Currently over 57% of tickets are being closed as duplicate.