Dell XPS 18 (1810, Early 2013) - Manual (Page 35)

You can check the powered stand’s status from:
• The light located at the front of the powered stand:
LED behavior Description
Solid white color on Computer is docked in the powered
stand
Off Computer is not docked in the
powered stand, or the power adapter
is not connected to the stand.
For more information on checking the battery status, see battery
charge indicator status table .
NOTE: If the LED is off and the computer is placed on the powered stand
with power, it may not be properly docked. Realign the computer on the
powered stand until the LED lights up.
Powered Stand (optional) │ 35