Very small one, but I believe it was necessary. Well, first the pictures...
If you've played the demo, you should know that to change the active players in battle, you need to click on that character's icon with either left or right mouse button, depending on which side of the field you want him/her to appear. Not anymore.
There are two slots on the left side of the (improved) character icons with a big "L" and "R" in the background. Click on one of these slots, and a dropbox will appear, listing all available characters. Pick one, and he/she will appear in battle on that side of the field. Unless it wasn't clear already, L means left and R right.
Basically it's the same thing you've been doing since the start, but I believe this makes it even more clear and comfortable.
As you may notice, there are some little "improvements" in the graphics too.
I will most likely update the demo with the new system, but I can't say when that would happen. I'm pretty busy doing the maps for two cities that are required for chapter 6.