Shows a list picker dialog. You can use the “Light Theme” property to have a light or dark background. Or you enable “Use Background Color” property to use the background color property as background dialog color.
Turning on the light theme allowed me to choose the 'back ground colour" and display it. So I guess this is the solution and hence marking it.
But Show List Picker Document is misleading. Also this does not resolve another issue : The “Text colour” is still black. The text colour of Notifier Show Alert is showing the set colour, but the Notifier Show List Picker does not. Building APK does not solve the “Text colour” issue.
Should I can create another topic about the Text colour issue ?
I am marking this solved for Notifier Background colour.