Bug 122687 Libraries dont appear to allow background colors on tables to be used
If I create a table and set the background color to blue in my library and then drag the table from the library to the report the background color does not go with it.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
assert getDefn( ).getProperty( propName ) == null;
		if ( userProperties == null )
			userProperties = new LinkedHashMap( );
		userProperties.put( propName, userProp );
	}
	/**
	 * Drops a user-defined property. The application must have previously
	 * removed all existing values for that property. The application must have
	 * previously validated that the user-defined property does exist, and is
	 * defined on this element.
	 * <p>
	 * Part of: User-defined property system.
	 * 
	 * @param prop
	 *            The user-defined property.
	 */
	public void dropUserPropertyDefn( UserPropertyDefn prop )
	{
		assert getDefn( ).allowsUserProperties( );
		assert userProperties != null;
		assert userProperties.get( prop.getName( ) ) == prop;
		userProperties.remove( prop.getName( ) );
	}
	/**
	 * Gets a user property definition defined on this class itself.
	 * <p>
	 * Part of: User-defined property system.
	 * 
	 * @param propName
	 *            The internal name of the user-defined property.