Have to drag items with mouse

I can't move items by clicking on them, I have to hold it down and drag it. Then the durability bar goes on top of the item when doing this. I believe this happened upon testing 1.9.
What I expected to happen was...:
I expected an item would move normally.

What actually happened was...:
It becomes hard to move an item, it can make things frustrating like trying to swap armour in PvP.

Steps to Reproduce:
1. Go into 1.9
2. Attempt to move items in your inventory (or chests and other things that display room to store items).
3. The bug should be found