diff -upr mlterm-3.1.8.org/xwindow/x_draw_str.c mlterm-3.1.8.underline/xwindow/x_draw_str.c
--- mlterm-3.1.8.org/xwindow/x_draw_str.c	2013-05-12 22:59:24.000000000 +0900
+++ mlterm-3.1.8.underline/xwindow/x_draw_str.c	2013-05-12 23:10:52.000000000 +0900
@@ -734,10 +734,11 @@ fc_draw_str(
 				}
 				else
 				{
+					const u_int line_height = ((ascent - bottom_margin) >> 4) + 1;
 					x_window_fill_with( window , fg_xcolor ,
-						x , y + ascent ,
+						x , y + height - line_height ,
 						current_width - x ,
-						((ascent - bottom_margin) >> 4) + 1 ) ;
+						line_height ) ;
 				}
 			}
 
@@ -1202,10 +1203,11 @@ xcore_draw_str(
 				}
 				else
 				{
+					const u_int line_height = ((ascent - bottom_margin) >> 4) + 1;
 					x_window_fill_with( window , fg_xcolor ,
-						x , y + ascent ,
+						x , y + height - line_height ,
 						current_width - x ,
-						((ascent - bottom_margin) >> 4) + 1) ;
+						line_height ) ;
 				}
 			}