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
* wizard's buttons and controls.
     *
     * @param savedState the saved UI state as returned by <code>aboutToStart</code>
     * @see #aboutToStart
     */
    private void stopped(Object savedState) {
        if (getShell() != null) {
            if (wizard.needsProgressMonitor()) {
                progressMonitorPart.setVisible(false);
                progressMonitorPart.removeFromCancelComponent(cancelButton);
            }
            Map state = (Map) savedState;
            restoreUIState(state);
            cancelButton.addSelectionListener(cancelListener);
            setDisplayCursor(null);
            cancelButton.setCursor(null);
            waitCursor.dispose();
            waitCursor = null;
            arrowCursor.dispose();
            arrowCursor = null;
            Control focusControl = (Control) state.get(FOCUS_CONTROL);
            if (focusControl != null) {
				focusControl.setFocus();
			}
        }
    }
    /**
     * Updates this dialog's controls to reflect the current page.
     */
    protected void update() {