How to change the Keyboard background color (roKeyboardScreen)?

You can't change the color of the individual rounded button backgrounds, nor the color of the transparent rounded background enclosing all the buttons.
However you can change the color of the entire screen background using the BackgroundColor attribute.

(This should be indicated in the https://sdkdocs.roku.com/display/sdkdoc/roAppManager documentation, but I see that it is missing the markers for Ke in the Screen Types column for the common screen attributes).

Ha, `keyboardKeyHighlightColor` is still undocumented, apparently http://stackoverflow.com/questions/39123573/how-to-develop-a-custom-keyboard-in-brightscript

"EnTerr" wrote:
Ha, `keyboardKeyHighlightColor` is still undocumented, apparently http://stackoverflow.com/questions/39123573/how-to-develop-a-custom-keyboard-in-brightscript

You can also consider create your own keyboard, take a look on my keypad example code:
https://github.com/lvcabral/RokuNumericKeypad