  * Commands like ess-display-help-on-object and list completion cannot be used while the user is entering a multi-line command.  The only real fix in this situation is to use another ESS process.

  * The ess-eval- commands can leave point in the ESS process buffer in the wrong place when point is at the same position as the last process output.  This proves difficult to fix, in general, as we need to consider all windows with window-point at the right place.

  * It's possible to clear the modification flag (say, by saving the buffer) with the edit buffer not having been loaded into S.

  * Backup files can sometimes be left behind, even when ess-keep-dump-files is nil.

  * Passing an incomplete S expression to ess-execute causes ESS to hang.

  * The function-based commands don't always work as expected on functions whose body is not a parenthesized or compound expression, and don't even recognize anonymous functions (i.e. functions not assigned to any variable).

  * Multi-line commands could be handled better by the command history mechanism.