Bug 134266 [Wizard] Page description not set if page message already set
Since page messages such as errors and warnings used to be displayed in the same widget as the page description, code was put in place in WizardDialog#updateDescriptionMessage() to avoid setting the page description if there was already a message. As of 3.2 M6 there is a separate widget for displaying error and warning messages and so the page description should always be set.
bundles/org.eclipse.jface/src/org/eclipse/jface/wizard/WizardDialog.java
* @param enabled <code>true</code> to enable the control, 
     *   and <code>false</code> to disable it
     * @see #restoreEnableState(Control, Map, String)
     */
    private void saveEnableStateAndSet(Control w, Map h, String key,
            boolean enabled) {
        if (w != null) {
            h.put(key, new Boolean(w.getEnabled()));
            w.setEnabled(enabled);
        }
    }
    /**
     * Captures and returns the enabled/disabled state of the wizard dialog's
     * buttons and the tree of controls for the currently showing page. All
     * these controls are disabled in the process, with the possible excepton of
     * the Cancel button.
     *
     * @param keepCancelEnabled <code>true</code> if the Cancel button should
     *   remain enabled, and <code>false</code> if it should be disabled
     * @return a map containing the saved state suitable for restoring later
     *   with <code>restoreUIState</code>
     * @see #restoreUIState
     */
    private Map saveUIState(boolean keepCancelEnabled) {
        Map savedState = new HashMap(10);
        saveEnableStateAndSet(backButton, savedState, "back", false); 
        saveEnableStateAndSet(nextButton, savedState, "next", false); 
        saveEnableStateAndSet(finishButton, savedState, "finish", false); 
        saveEnableStateAndSet(cancelButton, savedState,
                "cancel", keepCancelEnabled);