Scripting updates, guided tour fixes, and more.
My guess or hope is loading of images on start of layout.
In my project I create a tiled background on start of layout as a bottom bg.
In C3 you see the bg css color behind the tiled bg for second before the tile is loaded, this didn't happen in C2 with the same project, I had to do some work arounds to get over it, maybe now it'll work...