Q4.2.3: How do I make Gnus stay within a single frame?

The toolbar code to start Gnus opens the new frame—and it’s a feature rather than a bug. If you don’t like it, but would still like to click on the seemly icon, use the following code:

(defun toolbar-news ()
  (gnus))

It will redefine the callback function of the icon to just call gnus, without all the fancy frame stuff.