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
* selection events. Note that the number of columns in the button bar composite
     * is incremented. The Cancel button is created specially to give it a 
     * removeable listener.
     *
     * @param parent the parent button bar
     * @return the new Cancel button
     */
    private Button createCancelButton(Composite parent) {
        
        ((GridLayout) parent.getLayout()).numColumns++;
        Button button = new Button(parent, SWT.PUSH);
        button.setText(IDialogConstants.CANCEL_LABEL);
        setButtonLayoutData(button);
        button.setFont(parent.getFont());
        button.setData(new Integer(IDialogConstants.CANCEL_ID));
        button.addSelectionListener(cancelListener);
        return button;
    }
    /**
     * Return the cancel button if the id is a the cancel id.
     * @param id the button id
     * @return the button corresponding to the button id
     */
    protected Button getButton(int id) {
        if (id == IDialogConstants.CANCEL_ID) {
			return cancelButton;
		}
        return super.getButton(id);
    }
    /**