Bug 230218 [JFace] Test failures in PresentationsTestSuite and RCP Tests
bundles/org.eclipse.jface/src/org/eclipse/jface/resource/ColorRegistry.java
public Set getKeySet() {
        return Collections.unmodifiableSet(stringToRGB.keySet());
    }
    /**
     * Returns the color data associated with the given symbolic color name.
     *
     * @param symbolicName symbolic color name.
     * @return the <code>RGB</code> data, or <code>null</code> if the symbolic name
     * is not valid.
     */
    public RGB getRGB(String symbolicName) {
        Assert.isNotNull(symbolicName);
        return (RGB) stringToRGB.get(symbolicName);
    }
    
    /**
	 * Returns the color descriptor associated with the given symbolic color
	 * name. As of 3.4 if this color is not defined then an unspecified color
	 * is returned. Users that wish to ensure a reasonable default value should
	 * use {@link #getColorDescriptor(String, ColorDescriptor)} instead.
	 * 
	 * @since 3.1
	 * 
	 * @param symbolicName
	 * @return the color descriptor associated with the given symbolic color
	 *         name or an unspecified sentinel.
	 */
	public ColorDescriptor getColorDescriptor(String symbolicName) {
		return getColorDescriptor(symbolicName, DEFAULT_COLOR);
	}