Bug 65187 [Themes] Cascading*Registry leakage from Colors and Fonts pref page
Small leak on I20040529 For each ColorsAndFontsPreferencePage this is created, the cascading font and color registries are leaked. This is because the superclasses register a runnable with Display#disposeExec
bundles/org.eclipse.jface/src/org/eclipse/jface/resource/FontRegistry.java
return null;
    }
    /**
     * Find the first valid fontData in the provided list. 
     * If none are valid return the first one regardless.
     * If the list is empty return null.
     */
    public FontData[] bestDataArray(FontData[] fonts, Display display) {
        FontData bestData = bestData(fonts, display);
        if (bestData == null)
            return null;
        else {
            FontData[] datas = new FontData[1];
            datas[0] = bestData;
            return datas;
        }
    }
    /**
     * Creates a new font with the given font datas or <code>null</code>
     * if there is no data.
     * @return FontRecord for the new Font or <code>null</code>.
     */
    private FontRecord createFont(String symbolicName, FontData[] fonts) {
        Display display = Display.getCurrent();
        if (display == null)
            return null;
        FontData[] validData = bestDataArray(fonts, display);
        if (validData == null) {