The Messages feature is intended for displaying notification messages that are tied to specific form items. For example, if a user did not fill any fields or made any errors when entering a document, the platform will notify them.
The message pane contains the list of messages. The selected message is displayed in a balloon next to the form item that requires attention. Clicking the Next and Previous buttons moves between the form items that require correction.
Double-clicking a line in a list of messages moves you to the form item that must be filled. It is handy in forms that contain a large number of items that are not yet familiar to the user.
The messages are mostly used to inform users about operations that did not complete successfully (to explain the reasons and show which data should be corrected).
Managing messages from 1C:Enterprise script
The 1C:Enterprise script includes the UserMessage object, which is intended for managing messages. You can use it to create messages, link them to form items, and display them.