Regularly save your project and use the undo and redo buttons available on the bar at the top of your page
To save your project, be sure to click the save button located at the top right of your page regularly.
The red dot appears when changes that were made have not been saved
To undo the last modification made to your plan, click the undo arrow (left arrow) located at the top right of your page. If you want to redo the change you just undid, click the redo arrow (right arrow).
It is not possible to undo the last change if you saved your project after the change.
