platform.window:setBackgroundColor is a function that is part of platform.window.
This has been introduced in TI-Nspire OS 3.9 (Changes).
Sets the background color of the script's window.
|number||A number representing the color of the background. Must be an integer between 0 and 16777216|
NB: You can also use hexadecimal numbers instead of decimal ones for each of the arguments (from 0x000000 to 0xFFFFFF). The first two digits here represent the red, the third and fourth the green and the last two blue
Below is an example that sets the background color of the window to HTML silver.
platform.apilevel == '2.4' platform.window:setBackgroundColor(12632256) --0xC0C0C0 (HTML silver)