Bug 172273 Grid insert to masterpage dosen't display propertily [05]
Build Number: 2.2.0.v20070131-1050 Description: As the screenshot, insert a grid (3*3) in the master page.It can't be display propertily. Step to reproduce: 1. new a report and switch to masterpage 2. insert a grid (3*3) Actual result: Please refer to the screenshot, it's abnormal.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* @param child
	 *            The new derived element.
	 */
	protected void addDerived( DesignElement child )
	{
		if ( derived == null )
			derived = new ArrayList( );
		assert child != null;
		assert child.getExtendsElement( ) == this;
		assert !derived.contains( child );
		assert child.getDefn( ) == getDefn( );
		derived.add( child );
	}
	/**
	 * Removes a cached element that derives from this element.
	 * <p>
	 * Part of: Inheritance system.
	 * 
	 * @param child
	 *            The old derived element.
	 */
	public void dropDerived( DesignElement child )
	{
		assert derived != null;
		assert child != null;
		assert child.getExtendsElement( ) == this;
		assert derived.contains( child );
		derived.remove( child );
	}
	/**