gnus-summary-stop-at-end-of-message

gnus-summary-stop-at-end-of-message is a variable defined in `gnus-sum.el'.
Its value is

nil

Documentation:
If non-nil, don't select the next message when using `SPC'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.