buffers-tab questions

XEmacs 21.4.8 "Honest Recruiter" configured for `alpha-dec-osf5.1'. I've been looking at buffer tabs and gutter-items.el recently, and I'm confused. 1. Is the documentation for `buffers-tab-selection-function' wrong? It says: Documentation: *If non-nil, a function specifying the buffers to select from the buffers tab. This is passed two buffers and should return non-nil if the second buffer should be selected. The default value `select-buffers-tab-buffers-by-mode' groups buffers by major mode and by `buffers-tab-grouping-regexp'. Should line 3 really say "the *first* buffer should be selected"? I haven't actually tried to understand what `select-buffers-tab-buffers-by-mode' does, but here is the start of the defun (from gutter-items.el): (defun select-buffers-tab-buffers-by-mode (buffer-to-select buf1) Note that the first argument is `buffer-to-select', which is suggestive... While we're talking about documentation, this is confusing, the word "select" in particular. This variable is helping to control which tabs are displayed, right? It has nothing to do with selecting buffers by clicking on the tabs, and that's sort of what it sounds like. I would suggest changing the documentation for buffers-tab-filter-functions to say something like this: *If non-nil, a list of functions specifying the buffers to display in the buffers tab, depending on the context... or *If non-nil, a list of functions specifying the buffers for which to display tabs, depending on the context... 2. Do we need all of these customizations? We have buffers-tab-selection-function, default value select-buffers-tab-buffers-by-mode, buffers-tab-filter-functions, default value (list buffers-tab-selection-function). As far as I can tell, this is the only appearance of buffers-tab-selection-function. I think it would make sense to just keep the second of these as a customizable variable (keeping the first as a defvar for backwards compatibility), and have its default value be (list select-buffers-tab-buffers-by-mode). As far as I can tell from the lisp code in gutter-items.el, if you remove buffers-tab-selection-function from the list buffers-tab-filter-functions, then buffers-tab-selection-function is not used. So it looks redundant. Another reason for doing this is that as it stands, the customization options are really confusing, and also buggy. Do M-x customize-group buffers-tab and from the documentation, try to understand the difference between "Selection function" and "Filter functions". Here's the bug: if you set both buffers-tab-selection-function and buffers-tab-filter-functions to nil and save the customizations, then if you go to buffers-tab-filter-functions and say "Reset to standard settings", it resets it to (list buffers-tab-selection-function), but it evaluates this, so it gets set to '(nil). Then you get errors whenever you do anything, because every time the buffer tabs get redisplayed, the nonexistent function `nil' gets called. If you agree with my suggestion of removing the customizable variable buffers-tab-selection-function, should it be kept as a defvar, or as a defcustom with some other group (is there a customization group for obsolete options?), or as a defcustom in the current group, but labeled as obsolete? (I like the defvar choice, personally.) 3. Furthermore, I think the customization type for buffers-tab-filter-functions should be :type '(repeat function) instead of :type '(choice (const :tag "None" nil) sexp) 4. Finally, there was some discussion in comp.emacs.xemacs about changing the default behavior for buffer tabs -- in particular, to change the default value for buffers-tab-filter-functions to nil. Opinions on whether to do that? Comments? Should I submit a patch with these changes, or am I completely confused and things are actually perfect as they are? (I suppose if I don't hear anything, I'll submit a patch.) -- J. H. Palmieri Dept of Mathematics, Box 354350 mailto:palmieri＠math.washington.edu University of Washington http://www.math.washington.edu/~palmieri/ Seattle, WA 98195-4350