Daniel Borchmann <daniel.borchmann@tu-dresden.de> writes:

> Dear all,
>
> I regularly lose all my filters when I bury a sticky agenda and revive
> it later.  In that case, the variable `org-agenda-tag-filter' is set to
> nil, although it was non-nil before burying.
>
> I played around a bit, and found out that `org-agenda-tag-filter' is
> buffer-local (which is not a surprise).  When the agenda buffer is
> revived, the function `org-agenda-prepare' is called, which, among
> others, should reset the filters (provided that
> `org-agenda-persistent-filter' is set).  The beginning of the function
> is
>
> --->8---
> (defun org-agenda-prepare (&optional name)
>   (let ((filter-alist (if org-agenda-persistent-filter
>                           (list `(tag . ,org-agenda-tag-filter)
>                                 `(re . ,org-agenda-regexp-filter)
>                                 `(car . ,org-agenda-category-filter)))))
>   ...))
> ---8<---
>
> It seems to me that `org-agenda-tag-filter' is read *before* the old
> agenda buffer is poped up (i.e., made current), and thus results in a
> `nil' value.  Indeed, if I replace the definition of `filter-alist' by
>
> --->8---
> (let ((filter-alist (if org-agenda-persistent-filter
>                         (with-current-buffer
>                             (get-buffer org-agenda-buffer-name)
>                           (list `(tag . ,org-agenda-tag-filter)
>                                 `(re . ,org-agenda-regexp-filter)
>                                 `(car . ,org-agenda-category-filter))))))
>   ...)
> ---8<---
>
> then the bug (seems to) disappear.
>
> My question is now: is this correct, or did I understand something
> wrong?  If my understanding is correct, how this bug be fixed more
> elegantly?

It doesn't work at startup when agenda hasn't been built yet. The
following patch does seem to fix that. If it's ok, I can push it.