The status notification area on the panel is used to notify the user of non-critical events, such as the arrival of new email, and to monitor the status of background activities, such as a laptop battery charging. Recent versions of the GNOME desktop (2.12 or newer) can also pop up a small transient "balloon" attached to a notification icon, to give additional information and interaction choices related to an event.
![[Warning]](images/warning.png) | Warning |
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The utility of the notification area decreases rapidly when more than four icons are displayed at the same time. Icons that appear only temporarily, in response to specific events, are therefore preferable. |
Following the guidelines in this section will help to clarify the difference in the user's mind between information presented in the notification area, and controls and information presented on other parts of the panel.
There are three acceptable uses for the notification area:
Displaying a transient icon in response to an event (e.g. arrival of new mail in a monitored folder). Clicking the icon opens the most appropriate window to deal with the event (e.g. Inbox). The icon is removed when the state prior to the event is restored (e.g. no more unread mail in monitored folders).
Displaying an icon for the duration of a background activity (e.g. while a document is being printed). The icon is removed when the activity successfully completes, or replaced with a suitable error icon if the activity fails (optional tooltip or balloon to explain problem). Clicking the error icon (or balloon) opens the most appropriate window for the user to rectify the problem.
Displaying an ever-present icon to monitor a continuous background activity, such as a laptop battery being charged. Continous notification icon presence should always be controllable by a user preference. Only core GNOME applications may have this preference turned on by default; other applications should turn it off by default. Standard way of presenting this option would be nice.
In particular, you should probably use an applet instead of using a notification icon if:
your notification icon would need to be shown all the time, or would benefit from being shown all the time
and:
clicking your notification icon would do anything other than opening a window or dialog box directly associated with the icon or the event that caused it to appear (example?), or
multiple instances of the icon would either be required, or could be considered useful (for example, a clock-- a user might want to display a separate clock for each of multiple timezones)
Because the notification area is itself a panel applet, remember that the user may not have it on their desktop at all. Above all, therefore, only use notification icons to provide redundant, non-critical information.
Guidelines
Need some examples here. There have been suggestions in the past that notification icons should have a more muted colour scheme (possibly just B&W) than other objects on the panel-- good idea?Use table perspective for icons representing physical devices, for example a printer icon shown during printing, with the light source above and to the left of the represented object. See the section called “Perspective” for more about table perspective.
Use a flat, unshaded image for status monitors that take the form of a chart or graph, such as a CPU usage monitor. Clearly delimit the borders of the chart area.
Use shelf perspective, with overhead lighting, for all other icons. For example, an envelope shown when new mail arrives. See the section called “Perspective” for more about shelf perspective.
As with any part of the desktop, animation must be used sparingly to be effective, and redundantly to be accessible.
Guidelines
To avoid distracting the user, do not update notification icons that are monitoring a background activity any more than once per second by default. For any such icons that are perpetually shown, make the exact update frequency a user preference.
Do not animate notification icons that are not monitoring the status of a background activity.
Do not rely on animation, or any other change of appearance within a notification icon, as a means of alerting the user to a particular event.
All notification icons should respond to user interaction in a consistent way, similar to that for panel applets.
Guidelines
Perform the icon's default action when the user clicks the icon, or presses the Space key when it is focused. In general, an icon's default action should be to open a relevant window or dialog box, or to raise and focus that window or dialog box if it is already open but not focused. Examples of such windows and dialogs include:
the printer queue window, for a "printing in progress" icon
the default mail application's Inbox window, for an incoming email icon
the message window, for an incoming instant message icon
If the icon's associated window or dialog box is already raised and focused, close it when the user clicks the icon, or presses the Space key when the icon is focused. All windows associated with notification icons should be dismissable in this way, except for explicit apply dialog boxes. Those should always be dismissed by clicking their action or cancel buttons.
Present a context menu, containing at least the icon's default action, when the user right clicks the icon or presses Shift-F10 when the icon is focused.
If the icon's properties, or the properties of its associated application or document may be altered, include a menu item in its context menu, and show its property panel in response to Alt-Enter when the icon is focused.
FIXME: guidelines for appearance and interaction with libnotify-type balloons. All the guidelines shown here now are very early thoughts.
Random Thoughts
If an icon has displayed a balloon that is no longer visible, subsequently mousing over the icon should perhaps cause the last message to appear as a tooltip?
Need to think about notifications in the context of accessibility. The notification spec allows for notifications to be shown in different ways, perhaps we need to do something different for users relying on screenreaders or desktop magnification?
An icon may show a balloon to indicate an error in deference to showing an alert. For example, a printing-in-progress icon may show a balloon when there is a paper jam, but not when the printer is on fire - that should show an alert.
A balloon may be show when the icon is first displayed, if the icon's appearance is not the direct result of a user action. For example, the icon for an incoming email or instant message may be accompanied by a balloon. However, the appearance of a printing-in-progress icon would not be accompanied by a balloon, because its appearance was caused by the user choosing to print a document.
An icon may show a balloon if it has previously shown a balloon, and the condition recurs. For example, an incoming email icon which has remained visible, and was originally accompanied by a transient balloon, may show another balloon when another message arrives.