Bug 319509 [Viewers] Empty rows in CheckboxTableViewer with virtual table
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/CheckboxTableViewer.java
* @param table the table control
     */
    public CheckboxTableViewer(Table table) {
        super(table);
    }
    /* (non-Javadoc)
     * Method declared on ICheckable.
     */
    public void addCheckStateListener(ICheckStateListener listener) {
        checkStateListeners.add(listener);
    }
    
    /**
     * Sets the {@link ICheckStateProvider} for this {@link CheckboxTreeViewer}.
     * The check state provider will supply the logic for deciding whether the
     * check box associated with each item should be checked, grayed or 
     * unchecked. 
     * @param checkStateProvider	The provider.
     * @since 3.5
     */
    public void setCheckStateProvider(ICheckStateProvider checkStateProvider) {
    	this.checkStateProvider = checkStateProvider;
    	refresh();
    }
    
    /*
     * Extends this method to update check box states.
     */
    protected void doUpdateItem(Widget widget, Object element, boolean fullMap) {
    	super.doUpdateItem(widget, element, fullMap);