diff -urN cui87/cui.c cui88/cui.c
--- cui87/cui.c	Fri Mar 28 03:00:00 2014
+++ cui88/cui.c	Mon Mar 31 01:00:00 2014
@@ -105,15 +105,19 @@
 	int n = strlen(s);
 	char *s2 = NULL;
 
+cui_dbg_here("ck1");
 	if(!cui_visible_rect(obj, r1)) return;
+cui_dbg_here("ck2");
 	cui_rect_init(r2, x, y, n, 1);
 	if(!cui_rect_and(r1, r2, r2)) return; /* r1 and r2 --> r2 */
+cui_dbg_here("ck3");
 	if(cui_clip){
 		*r1 = *cui_clip;
 		r1->x = cui_lx(obj, r1->x);
 		r1->y = cui_ly(obj, r1->y);
 		if(!cui_rect_and(r1, r2, r2)) return;
 	}
+cui_dbg_here("ck4");
 
 	s += r2->x - x;
 	if(r2->x + r2->w < x + n){
diff -urN cui87/dbg.c cui88/dbg.c
--- cui87/dbg.c	Sun Mar 30 22:00:00 2014
+++ cui88/dbg.c	Mon Mar 31 01:00:00 2014
@@ -5,6 +5,7 @@
 #include <stdarg.h>
 
 static FILE *fp = NULL;
+int cui_dbg_enable = 1;
 
 int
 cui_dbg_open(int ac, char **av)
@@ -13,6 +14,9 @@
 	int i;
 	char *nc_opt = "localhost 12345";
 
+	for(i=1; i<ac; i++) if(strcmp(av[i], "-dbg-en0") == 0) break;
+	if(i<ac) cui_dbg_enable = 0;
+
 	for(i=1; i<ac; i++) if(strcmp(av[i], "-dbg") == 0) break;
 	if(i >= ac) return 0;
 
@@ -34,6 +38,7 @@
 	va_list ap;
 
 	if(!fp) return;
+	if(!cui_dbg_enable) return;
 	va_start(ap, fmt);
 	vfprintf(fp, fmt, ap);
 	fflush(fp);
diff -urN cui87/dbg.h cui88/dbg.h
--- cui87/dbg.h	Sun Mar 30 22:00:00 2014
+++ cui88/dbg.h	Mon Mar 31 01:00:00 2014
@@ -1,6 +1,10 @@
 #ifndef __DBG_H__
 #define __DBG_H__
 
+#define cui_dbg_here(s)	cui_dbg("%s() %s L%d : %s\n", __func__, __FILE__, __LINE__, s)
+
+extern int cui_dbg_enable;
+
 int cui_dbg_open(int ac, char **av);
 void cui_dbg_close(void);
 void cui_dbg(char *fmt, ...);
diff -urN cui87/term.c cui88/term.c
--- cui87/term.c	Mon Mar 31 00:00:00 2014
+++ cui88/term.c	Mon Mar 31 01:00:00 2014
@@ -53,7 +53,9 @@
 
 	if(*attr == -1) return;
 	*lp = '\0';
+cui_dbg_enable = 1;
 	cui_draw_str(obj, x, y, p->lbuf, *attr & ~UPDATE_FLG);
+cui_dbg_enable = 0;
 	*attr = -1;
 }