Versioning
LestForm Designer automatically stores past versions of the forms inside projects on every save operation.
The "Save" option is smart enough to not create too many versions on multiple small changes, to be sure to create a new version or to add a comment to a specific version click on "Save with comment..."
From the project page, expand the down arrow next to each form and select "Versions..."
The versions window will show all available versions which can be previews, compared and, if needed, restored.