I've noticed that TOC checkboxes behave differently with nested layers in 3.1. It's rather hard to explain but when you see it in action it's very awkward. Say you have a tree structure like this:
A -B --C --D
In 3.0 and earlier you could check or uncheck any layer at any time. Nice and simple.
In 3.1 this behavior has changed. Now a layer can only be checked if one of its sublayers are checked. This forces the user to expand the tree to its lowest level and check backwards. In addition, a parent layer will automatically uncheck when all of its children are unchecked. The top layer however (A) follows the 3.0 behavior and can be toggled at will.
It's extremely awkward and makes navigation difficult. Add more sub-layers and it gets even messier. Please, please bring back the old behavior from 3.0.
