A right click on the "Save" icon 
displays the "Snapshot" function.
The "Snapshot" function is designed to save different versions of the edit session each "x" minutes automatically.
Thus, it is possible to reload an edited version.
To reload a previous version of an edit session :
•Do a right-click on the "save" icon .
A "Load Snapshot save" window will appear with all the different versions.
•Select the version to reload.
•Double-click on it or click on "OK".