When working in one of the edit windows, such as when you’re working as an author creating new content, you should click the Cancel icon or Save icon to exit the page.
The reason for this is that Joomla locks the content while you are editing it, preventing other users such as editors and publishers from accessing it at the same time. This function is referred to as global checkin, and it’s managed with the Global Checkin tool found on the Site menu in the backend.
There are times when exiting edit windows improperly could result in content being locked to others. The following are just a few cases in which this could occur:
• The user accidentally closes his or her browser window before canceling or saving a transaction.
• The user uses the browser navigation functions (such as the Back button or a bookmark) to move away from the site before canceling or saving the transaction.
• A power failure knocks out the user’s PC at the wrong time or there is an interruption in the user’s Internet service.
Whatever the reason, not saving or canceling a transaction properly can lock users from accessing the article later. The checkin function is available in the backend in the Site menu when you’re logged in as an administrator or higher.