>1. There is no visual separation in the lower pane between the header information (forum, category, title, etc.) and the message text. They flow continuously as though they are all the same thing, which they are not. Even a separator line would do IMO.

This is normal.

>2. Is there an option to turn off those background globes in the upper (treeview) pane? I find them distracting.

This is because your browser is still using the cache. Force a right click refresh to get the new version.

>3. This one actually seems to be a bug. After scrolling around in the treeview pane a bit, part of the window took on a gray background. It does not appear to be intentional because the gray background starts in the middle of a line.

This is related to point 2.

>How would you like us to bring these things to your attention? It might be unwieldy to have a new thread for everything anyone notices.

Right here