disable it buffer-locally.
(ibuffer-mouse-popup-menu): Use `=' instead of `eq' to compare
`eventpt' and point.
* ibuf-ext.el (ibuffer-remove-duplicates): New function.
(ibuffer-set-filter-groups-by-mode): Use it instead of
`delete-duplicates' so we don't require cl library at runtime.
(ibuffer-insert-filter-group-before): Don't use `position' so we
don't require cl library at runtime.
* chistory.el (command-history-mode): Add interactive spec.
Improve doc string.
(Command-history-setup): Don't switch buffers. Take
no args, and do not set major-mode, mode-name or the local map.
(command-history-mode): New function, does some of those things
Command-history-setup used to do.
(list-command-history): Call command-history-mode, not
Command-history-setup.
