it seems that using ncurses_waddch($window, ascii space) do not set the attribute properly without forcing the wrefresh.
if you use these function with, for example ascii "A" (65), its not necessary the wrefresh after the ncurses_waddch.
using wrefresh after all waddch causes overhead cpu usage.

example:

initialize, create window, set color

// the window was create with 20 lines and 60 colums...so
//$nr_linhas=20; $nr_colunas=60;

ncurses_wborder($win, 0,0,0,0,0,0,0,0);
$l = 1;
while($l < $nr_linhas - 1) {
$c = 1;
   ncurses_wmove($win, $l, 1);
   while($c++ < $nr_colunas - 1) {
      ncurses_waddch($win, 65);
      //ncurses_wrefresh($win); //only here attribute is set
   }
   $l++;
   // using wrefresh here nothing change
}
// using wrefresh here nothing change

using waddstr seems the same thing.
if you trie to use waddch once the attribute is set ok.
but using routine to put more than 13 charachters its necessary use wrefresh (after 13 characters).
:)