Merge from origin/emacs-26

0589de5 (origin/emacs-26) Fix markup of fake keys in the ELisp manual
82d4b98 Avoid errors in Auto Revert mode
a3b1935 Mention empty strings in file name expansion, emacs lisp refe...
a38da0d cc-mode.texi: Work around makeinfo alignment bug.  Fix proble...
464ee80 Warn against recursive invocations of 'buffer-list-update-hoo...
60b5c10 Provide more details in doc-string of 'delete-windows-on' (Bu...
f0be0f1 Improve documentation of 'delete-windows-on'
f1bddc7 * lisp/frame.el (make-frame-command): Doc fix.  (Bug#34715)
2848623 Avoid undefined behavior in gdb-mi.el
dbf1837 * lisp/window.el (fit-frame-to-buffer): Make doc-string more ...
099ef44 Minor spelling and grammar fixes (bug#34756)
52fd400 Minor improvement of documentation of '(when CONDITION . SPEC)'
f872b65 Improve documentation of 'auto-coding-functions'
04cad5e Fix visiting XML files with non-Unix EOL format
a89fabe Update example major mode code in Elisp manual

# Conflicts:
#	lisp/autorevert.el
#	lisp/window.el

1 files changed, 10 insertions, 0 deletions

diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 95379b342b3..c4cb83977fc 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -4894,6 +4894,16 @@ and the buffer position where the @code{display} property was found,
 respectively.  Both positions can be different when @code{object} is a
 string.
 
+Note that @var{condition} will only be evaluated when redisplay
+examines the text where this display spec is located, so this feature
+is best suited for conditions that are relatively stable, i.e.@:
+yield, for each particular buffer position, the same results on every
+evaluation.  If the results change for the same text location, e.g.,
+if the result depends on the position of point, then the conditional
+specification might not do what you want, because redisplay examines
+only those parts of buffer text where it has reasons to assume that
+something changed since the last display cycle.
+
 @node Display Margins
 @subsection Displaying in the Margins
 @cindex display margins