To define a color for a simple component, use the Color selection editor.
Reduced view of the color selection-editor
A color is defined by its RGB value (red, green, blue). The RGB value can be entered manually (separated by comma). The current color is the background color of the button.
With the color value -1, -1-1, you can define the standard background color of the current Look & Feel.
The graphical selection of the color is activated through the button (red button).
Color selection-editor