It appears that what you have to do is
1. select your choice from the dropdown menu and then
2. click messages in the left menu to set your choice.
Very circuitous since you selct "messages" on the left if even if you choose "topics" in the drop down menu. Not very intuitive. "Messages" is being used both as a category name for all messages however they are viewed and as a distinct way of viewing one part of that category. A word needs to mean only one thing within a context.
Also not intuitive to have a different landing page from the home page.