Bug 71354 [painting] IAE in StyledText.getBidiSegments upon revert
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaSourceViewer.java
* @param store the store to read from
     * @param key the key used for the lookup in the preference store
     * @param display the display used create the color
     * @return the created color according to the specification in the preference store
     * @since 3.0
     */
    private Color createColor(IPreferenceStore store, String key, Display display) {
    
        RGB rgb= null;      
        
        if (store.contains(key)) {
            
            if (store.isDefault(key))
                rgb= PreferenceConverter.getDefaultColor(store, key);
            else
                rgb= PreferenceConverter.getColor(store, key);
        
            if (rgb != null)
                return new Color(display, rgb);
        }
        
        return null;
    }
	/*
	 * @see org.eclipse.jface.text.source.ISourceViewerExtension2#unconfigure()
	 * @since 3.0
	 */
	public void unconfigure() {
		if (fOutlinePresenter != null) {
			fOutlinePresenter.uninstall();