Hi,
1. I have no idea what that is, maybe the post editor recognizes a plugin shortcode or something, but I have not seen that before. Does that show on every post editor, or only on specific posts?
2. Sure, optimally, you can load a new theme that has ‘vertical’ layout in it’s name. You can however change the layout of the existing theme here as well. In that case however make sure to change the font colors, as they will be most likely different from what you need. Some fields might be also disabled, you want to check those as well.