The Client can be configured to automatically quit in case of user inactivity for a specified length of time, if no signal is received from an input device (keyboard, mouse, joystick).

To do so:

1. Go to Settings → Options → User interface (1–2).
   
2. In the  Time until automatic quit field, enter the duration of user inactivity after which the Client should be quit (3). 
   If the field is blank or equals 00:00, the Client will not be quit.
3. Click the Apply button.