When a modification is made on document – added comment, attachment, etc – we must save the changes.
We can easily save all changes made by pressing CTRL+S keys on keyboard or by clicking on Save button in toolbar.
If we do not want to save changes we can just close the document by clicking on X in the upper right corner of the document view or pressing CTRL+W simultaneously or by clicking on menu Document>Quit. A pop-up appears asing us if we would like to save changes. Press No if you won’t save the changes.