In the B4J project you have to change the color of the B4XComboBox with a piece of code even though the designer shows the color.
This is the designer image:
This is how it looks like without the change:
And this is how it looks like with the code change:
In the B4XPage_Created subroutine you have to add the following line:
CSSUtils.SetBackgroundColor(cbxtables.cmbBox, fx.Colors.From32Bit(0xFFFFE884))
The libraries jFX and CSSUtils are used for this to work. Declare the variable fx as JFX.
Note: the xui.Color_ARGB(100,255,255,255) method evaluates as an Int whereas the fx.Colors.From32Bit evaluates as a Paint type.
Happy coding!