If you need to do a backup of your WS-task or would like to go back to a previous design there are some options described below:
Use these two functions to go back and forth between your last changes. (as soon as you close the design dialogue, this feature is not available)
You can save your current trench design at any time by exporting the task as an XML file. This is a simple way to do a backup of your WS design at any time. Consider doing it before doing a major change in your design.
Press model and "Save as" then choose those trenches that you want to save as a file.
You can then import them again by pressing "Import" from the same dropdown menu as shown below.