Bug 122850 Table/list should not be able to be inserted in Master Page mode.
Description: Table/list should not be able to be inserted in Master Page mode. Steps to reproduce: 1. New a report and transfer to Master Page mode. 2. New a datasource and dataset 3. Drag a list/table to page header/footer, bind it to dataset and drag some columns inside. 4. Save and preview Expected result: Insert list/table item in master page should be forbidden. Actual result: They are allowed and preview showed "undefine" in page
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* {@link Module#getElementByID}to obtain and element given an element ID.
 * </dd>
 * </dl>
 * 
 * <h3>Element Visitor</h3>
 * 
 * A visitor class is a design pattern that is useful for implementing certain
 * kinds of algorithms that need to "touch" many different elements. One could
 * code the element by adding methods to each element, but doing so is
 * cumbersome, complex, and error-prone. Better is to define a <em>visitor</em>
 * class that has methods for each element. One simply <em>applies</em> the
 * visitor to an element, and the element then calls its specific "visit" method
 * in the visitor. For example, the design engine uses a visitor to write the
 * design to an XML file.
 * 
 * <h3>API Handles</h3>
 * 
 * This class, and its subclasses, are low-level classes that maintain the state
 * of the design. Property and slot methods are generic so that they work for
 * all elements. Modifications must be done through commands. The application,
 * however, wants to work with a simpler set of objects, and wants to work with
 * specific "getter" methods to get properties. The application also simply
 * wants to call a "setter" method to make a change.
 * <p>
 * The API handle package provides a set of "facade" classes that give this
 * high-level view. Therefore, the application will seldom work with this class
 * directly. Instead, it will work with the handle produced by calling the
 * {@link #getHandle( Module module )}method.
 * 
 * <h3>Semantic State</h3>