Bug 166015 Refactor designer actions to eclipse command framework
Eclipse command framework provide a more explicit way to manage UI actions contributions, we can take it's advantage to make our actions code more clean and maintainable.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dnd/InsertInLayoutUtil.java
}
		else if ( insertObj instanceof String )
		{
			
			return performInsertString( (String) insertObj, target );
		}
		else if ( insertObj instanceof Object[] )
		{
			return performMultiInsert( (Object[]) insertObj,
					target,
					targetParent );
		}
		else if ( insertObj instanceof IStructuredSelection )
		{
			return performMultiInsert( ( (IStructuredSelection) insertObj ).toArray( ),
					target,
					targetParent );
		}
		return null;
	}
	/**
	 * Creates a object, "Add" operation to layout needs to handle later.
	 * <p>
	 * Must make sure operation legal before execution.
	 * </p>
	 * 
	 * @param insertObj
	 *            object insert to layout
	 * @param editPart
	 *            target EditPart