Located at the top of the Editor are Zoom, Undo, and Redo controls to help make an easy design process for both admins and users.
Zoom can be controlled by hitting the plus or minus sign. You will see the percentage zoomed shown in the middle of these two buttons.
To the right of this you will have Undo/Redo controls. All Projects are auto-saved as soon as any edits are made so you can Undo/Redo even after a refresh or closing the project.