Steps to reproduce:
1. Designer settings: TextColor=blue, background=white
When you run the test app, you wouldn't be able to see anything on the view because the text is white on white.
2. Now change its background to Blue and run the app again, you'll see white text clearly on blue.
The text properties always appear though it doesn't mean that the custom view actually uses them. Currently only the TextSize is retrieved from the text properties.
You can access ComboBox.cmbBox and further modify it.