The Notifications Settings window:
You can use default settings or modify the settings for all enabled accounts separately.
An icon without a red cross means direct settings and an icon containing the red cross means explicitly forbidden.
You can set three forms of notifications, Popup windows, notification icons in tray and playing sounds.
You can disable notifications when a full-screen application is detected running on the computer by checking the appropriate box.
You can cause pop-up windows to be hidden after a certain period of time by checking the appropriate field and specifying the time value in milliseconds.
There are many types of actions that you can set notifications for. You may choose a combination of notifications for each event according to their level of importance to you.
Moreover, you can disable /enable the appearance of sound and popup notification while the main window is active.