I'm not sure what you mean by "disposing the usercontrol". A CloseAction of RemovePane just means that we will remove it from the XamDockManager's tree and any references that we are maintaining it so that it is not rooted. A ContentPane is not an IDisposable nor does it evaluate the values of its Content, Header, etc. properties to see if they are IDisposable and assume that those should be disposed. Do you mean that you are using a .net memory profiler and it shows that your usercontrol is still rooted? If so, what is the rooting path(s)? While it is possible that something in our code is rooting a ContentPane it could also be that something in the WPF framework or possibly even because of something within the ContentPane itself is rooted. In order to know what is happening we'll need to see a sample that demonstrates the issue.