System Tray Icon
The system tray provides quick access to functionality integrated into the workspace that's both highly visible to the user and frequently changed, like enabling/disabling WiFi and Bluetooth, or whether or not to show notifications. See architecture for an overview of plasma workspace components.
Is this the right control?
An application should only add an icon to the System Tray if the user needs to frequently access the application, or if the user is interested in status changes within the application.
- On left click, open the application itself, or a panel that allows quick access to common features.
- On right click, open a context menu.
- For application like media players, enable the user to change the volume while scrolling over the icon.
Use a monochrome, shade black icon and use color only to communicate state.