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
* 
	 * @param element
	 *            The potential container.
	 * @return True if this element is contained in the container either
	 *         directly or indirectly. False if this element is not contained.
	 *         If the given element is this element itself, return true.
	 */
	public boolean isContentOf( DesignElement element )
	{
		DesignElement e = this;
		while ( e != null )
		{
			if ( e == element )
				return true;
			e = e.container;
		}
		return false;
	}
	/**
	 * Returns the value of a property as a number (BigDecimal).
	 * 
	 * @param module
	 *            the module
	 * @param propName
	 *            the name of the property to get
	 * @return the property as a BigDecimal, or null if the value is not set or
	 *         cannot convert to a number
	 */
	public BigDecimal getNumberProperty( Module module, String propName )
	{