Bug 78225 [Preferences] Clarify spec w.r.t. threads and change notification
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/IPreferenceStore.java
* the preference's current value was its old default value, in which
     * case it changes to the new default value. If the preference's current
     * is different from its old default value, its current value is
     * unaffected. No property change events are reported by changing default
     * values.
     * </p>
     *
     * @param name the name of the preference
     * @param defaultObject the new default value for the preference
     */
    public void setDefault(String name, String defaultObject);
    /**
     * Sets the default value for the boolean-valued preference with the
     * given name. 
     * <p>
     * Note that the current value of the preference is affected if
     * the preference's current value was its old default value, in which
     * case it changes to the new default value. If the preference's current
     * is different from its old default value, its current value is
     * unaffected. No property change events are reported by changing default
     * values.
     * </p>
     *
     * @param name the name of the preference
     * @param value the new default value for the preference
     */
    public void setDefault(String name, boolean value);
    /**
     * Sets the current value of the preference with the given name back
     * to its default value.