Bug 209106 BIRT - User properties defined in a library are not seen in properties view
In the attached library there is a grid container. The text control and the row of the table in the grid have two user properties each. We can see them in the library but not when we drag them in to a design. The property does not show up in the properties view
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
assert child.getExtendsElement( ) == this;
		assert derived.contains( child );
		derived.remove( child );
	}
	/**
	 * Sets the parent element. This version should be used to implement a
	 * command to change the parent element. The caller must have validated that
	 * the new parent is valid for this element.
	 * <p>
	 * Part of: Inheritance system.
	 * 
	 * @param base
	 *            The new parent element, or null if the element is to have no
	 *            base element.
	 */
	public void setExtendsElement( DesignElement base )
	{
		DesignElement oldExtends = getExtendsElement( );
		if ( base == oldExtends && base != null )
			return;
		if ( oldExtends != null )
			oldExtends.dropDerived( this );
		if ( base == null )
		{
			extendsRef = null;
		}
		else
		{
			
			assert base.getDefn( ) == getDefn( );