--- RichString.c.orig	2008-03-09 03:23:49.000000000 +0100
+++ RichString.c	2008-11-18 12:30:21.000000000 +0100
@@ -89,7 +89,7 @@
 inline void RichString_appendn(RichString* this, int attrs, char* data_c, int len) {
    int last = MIN(RICHSTRING_MAXLEN - 1, len + this->len);
    for (int i = this->len, j = 0; i < last; i++, j++)
-      this->chstr[i] = data_c[j] | attrs;
+      this->chstr[i] = ((data_c[j] > 31) ? data_c[j] : '?' ) | attrs;
    this->chstr[last] = 0;
    this->len = last;
 }