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
* The <code>WizardDialog</code> implementation of this <code>Window</code>
     * method calls call <code>IWizard.addPages</code> to allow the current
     * wizard to add extra pages, then <code>super.createContents</code> to create
     * the controls. It then calls <code>IWizard.createPageControls</code>
     * to allow the wizard to pre-create their page controls prior to opening,
     * so that the wizard opens to the correct size. And finally it
     * shows the first page.
     */
    protected Control createContents(Composite parent) {
        
        
        
        wizard.addPages();
        Control contents = super.createContents(parent);
        
        createPageControls();
        
        showStartingPage();
        return contents;
    }
    /* (non-Javadoc)
     * Method declared on Dialog.
     */
    protected Control createDialogArea(Composite parent) {
        Composite composite = (Composite) super.createDialogArea(parent);
        
        pageContainer = createPageContainer(composite);
        GridData gd = new GridData(GridData.FILL_BOTH);
        gd.widthHint = pageWidth;
        gd.heightHint = pageHeight;