gnus-summary-tool-bar

gnus-summary-tool-bar is a variable defined in `gnus-sum.el'.
Its value is

gnus-summary-tool-bar-retro

Documentation:
Specifies the Gnus summary tool bar.

It can be either a list or a symbol referring to a list. See
`gmm-tool-bar-from-list' for the format of the list. The
default key map is `gnus-summary-mode-map'.

Pre-defined symbols include `gnus-summary-tool-bar-gnome' and
`gnus-summary-tool-bar-retro'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 23.1 of Emacs.