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
/**
	 * Gets the cached parent element. There will be no parent if either 1) the
	 * element does not extend from another user-defined element, or 2) the
	 * extends element is undefined.
	 * <p>
	 * Part of: Inheritance system.
	 * 
	 * @return parent element
	 */
	public DesignElement getExtendsElement( )
	{
		if ( extendsRef == null )
			return null;
		return extendsRef.getElement( );
	}
	/**
	 * Gets the name of the element that this element extends.
	 * 
	 * @return The name of the extended element.
	 */
	public String getExtendsName( )
	{
		if ( extendsRef == null )
			return null;
		return StringUtil.buildQualifiedReference( extendsRef
				.getLibraryNamespace( ), extendsRef.getName( ) );
	}
	/**
	 * Returns the optional element name.
	 * <p>