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
* 
	 * @return <code>true</code> if the property of current element is
	 *         editable. Otherwise <code>false</code>.
	 */
	public boolean canEdit( )
	{
		return !isRootIncludedByModule( );
	}
	/**
	 * Determines if this element can be dropped from its container.
	 * 
	 * @return <code>true</code> if it can be dropped. Returns
	 *         <code>false</code> otherwise.
	 */
	public boolean canDrop( )
	{
		
		
		if ( isRootIncludedByModule( ) )
			return false;
		
		
		if ( isVirtualElement( ) )
			return false;
		
		
		if ( container instanceof TemplateParameterDefinition )
		{
			assert containerSlotID == TemplateParameterDefinition.DEFAULT_SLOT;
			return false;