Saving in MockFlow editor
To save changes made to a project, user has to press the ' Save' button from the top menu.
While the purpose is to prevent unintended changes in your wireframe being saved, MockFlow actually autosaves all your work in the background as revisions. So incase you forgot/unable to save your work, you can always use the "Revision History" for accessing and restoring your unsaved changes. Learn more from here.
Keyboard Shortcut for saving in Windows: Ctrl+S
Keyboard Shortcut for saving in Mac: Cmd+S
To save changes, click either of the buttons shown in the below screenshot: