The "Web Console" is pretty awesome, but I don't see a way to close the detailed view things. Also I don't see POST contents in the detailed view things.
You should be able to close the detail panel by using the OS-standard close control on the window. If you don't see that control, that's a bug! (The control certainly shows up on my Mac.)
Request/response bodies are not logged by default because they can be large. If you right-click on the output area, the context menu there has an option to log request/response bodies. I believe beta 7 is the one in which we put in a change so that only the first 1MB of the body is logged.