I just ran into a bug report about this, so I thought it might be a good idea to post about it. The bug report detailed a case where the following configurations were not being merged correctly: Parent POM: configuration items itemone/item itemtwo/item /items /configuration Child POM: configuration items itemthree/item /items /configuration Expected result, according to MNG-2591: configuration items itemone/item itemtwo/item itemthree/item /items /configuration By default, Maven would simply replace the parent's items sub-elements with those from the child, resulting in only one item: three. This is mainly because Maven treats all plugin configuration as XML DOM content, without any idea of what makes up a list of related items, and what is just complex configuration. Moreover, sometimes you want to override the entire list instead of merely appending to it... it's a difficult balance to strike.