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
{
		if ( obj == null )
			return false;
		if ( obj == this )
			return true;
		if ( obj instanceof DesignElementHandle )
			return ( (DesignElementHandle) obj ).getElement( ) == this;
		return false;
	}
	/**
	 * Returns the slot that contains the given content element.
	 * 
	 * @param content
	 *            the element to find
	 * @return the number of the slot that contains the element, or -1 if this
	 *         element does not contain the content element.
	 */
	public int findSlotOf( DesignElement content )
	{
		IElementDefn defn = getDefn( );
		int count = defn.getSlotCount( );
		for ( int i = 0; i < count; i++ )
		{
			if ( getSlot( i ).contains( content ) )
				return i;
		}
		return -1;
	}
	/**
	 * Checks whether the property of current element is editable.