The preview editor allows you to make changes to a scene in the preview XSplit Broadcaster mixer without those changes being seen on the live XSplit Broadcaster mixer until you choose to push them to the live mixer.
To open the preview editor, right click on any scene and choose Preview Editor:
And it will take you there:
The preview editor mixer functions in a similar manner to the live mixer with a few different options.
Here, you can load or save a scene made in the preview editor:
Any changes made to the scene in the preview editor can be applied instantly or discarded:
Using the current scene dropdown box, you can switch between different scenes to edit:
As in the lie mixer, you can also choose which transitions you want to apply and you can also add them to your list of favorite transitions:
Finally, clicking on the downward arrow [v] (next to Go Live) gives you a variety of actions that you can pre-program to be done after you click on Go Live:
You can set the the preview window to close, reload, change to another scene, or swap with the live window when Go Live is clicked.