company--posn-col-row: add comment

diff --git a/company.el b/company.el
index 0991f6db8d01c9539741761ac0d00e0fee3aa4ff..af125d0f5f9d3ee6505e5667d87b27b02c23cfde 100644 (file)
--- a/company.el
+++ b/company.el
@@ -773,6 +773,8 @@ means that `company-mode' is always turned on except in `message-mode' buffers."
 
 (defun company--posn-col-row (posn)
   (let ((col (car (posn-col-row posn)))
+        ;; `posn-col-row' doesn't work well with lines of different height.
+        ;; `posn-actual-col-row' doesn't handle multiple-width characters.
         (row (cdr (posn-actual-col-row posn))))
     (when (and header-line-format (version< emacs-version "24.3.93.3"))
       ;; http://debbugs.gnu.org/18384