Bug 163345 [Field Assist] - API - Deprecate DecoratedField and related classes
If ControlDecoration is adopted in replacement of DecoratedField by all existing SDK clients, then we should deprecate DecoratedField.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/FieldAssistColors.java
Color src = JFaceColors.getErrorText(control.getDisplay());
		int destRed = dest.getRed();
		int destGreen = dest.getGreen();
		int destBlue = dest.getBlue();
		
		int alpha = (int) (0xFF * 0.10f);
		
		destRed += (src.getRed() - destRed) * alpha / 0xFF;
		destGreen += (src.getGreen() - destGreen) * alpha / 0xFF;
		destBlue += (src.getBlue() - destBlue) * alpha / 0xFF;
		return new RGB(destRed, destGreen, destBlue);
	}
	/**
	 * Return the color that should be used for the background of a control to
	 * indicate that the control is a required field and does not have content.
	 * <p>
	 * This color is managed by FieldAssistResources and should never be
	 * disposed by clients.
	 * 
	 * @param control
	 *            the control on which the background color will be used.
	 * @return the color used to indicate that a field is required.
	 */
	public static Color getRequiredFieldBackgroundColor(Control control) {
		final Display display = control.getDisplay();
		
		if (display.getHighContrast()) {
			return control.getBackground();
		}