Various technologies and techniques are disclosed that allow a user interface in a managed runtime environment to display content from two or more different partitioned process spaces. A software application having a user interface operates a managed runtime environment. A window handle allows a user interface of the application to display content from different partitioned process spaces at a same time. Information from the partitioned process spaces can be integrated within the user interface while preserving a level of isolation between the partitioned process spaces. This is accomplished by providing a first portion of a content container for the user interface with a host control that contains the window handle and resides in a first partitioned process space of a main window. A second portion of the content container is provided with a source control that provides the window handle and resides in a second partitioned process space.