If you want to open a metanode, you simply double-click it. But unfortunately on wrapped nodes, double-click just opens the configuration dialog. To see the contents on the node, you have to right-click, select Wrapped Node and then Open. So after a few months of frustratingly doing this every time, today I found out this litte trick:
Press and hold the Ctrl-key and double-click the wrapped node... TADAAAA!