To make speedbar show an R buffer’s functions, variables, etc, you need to add R to the set of supported extensions; for instance, add to your .emacs
By default, speedbar will split the list of functions into groups if there are more than 10. If you do not like this behavior, set the variable
to a larger number.
These settings will also work with sr-speedbar, a mode to make speedbar show in the current frame.
Note that you do not need to do anything special for Emacs Code Browser to work with ESS/R.