Hi Stacey,
Cornerstone is their new front-end editor since version 4.0. It’s not compatable with the pages you have made in X3 that means you can’t edit exsisting pages with it. The next problem is that you can’t have activated cornerstone(4.0+) and X-shortcodes (X3) but you need to activate cornerstone to makes everything working. Cornerstone is a complete new concept and completely different and the meaning of all is that you bit by bit build your old pages new with cornerstone. The solution for now is activate Cornerstone, deactivate X-shortcodes and use virtual composer classic mode as editor because that’s working in both versions. Themeco has a custom Virtual composer where the X shortcodes are included. Don’t forget to configur x in the virtual composer settings.
Notice that the name of the content band in X shortcodes calls VC Row in the virtual composer but it’s the same feature.
I didn’t use Cornerstone yet and I don’t know if I going to. I don’t like front-end editors but I need to spay that Cornerstone realy is a revolution.
Don’t hesitate to contact me if something isn’t clear.