--- rxvt-unicode/src/screen.C	2011/07/08 00:08:40	1.388
+++ rxvt-unicode/src/screen.C	2011/07/10 00:40:17	1.393
@@ -205,7 +205,7 @@
       talloc = new rxvt_salloc (ncol * sizeof (text_t));
       ralloc = new rxvt_salloc (ncol * sizeof (rend_t));
 
-      row_buf   = (line_t *)rxvt_calloc (total_rows + nrow, sizeof (line_t));
+      row_buf   = (line_t *)rxvt_calloc (total_rows       , sizeof (line_t));
       drawn_buf = (line_t *)rxvt_calloc (nrow             , sizeof (line_t));
       swap_buf  = (line_t *)rxvt_calloc (nrow             , sizeof (line_t));
 
@@ -277,7 +277,7 @@
         }
 
       line_t *old_buf = row_buf;
-      row_buf = (line_t *)rxvt_calloc (total_rows + nrow, sizeof (line_t));
+      row_buf = (line_t *)rxvt_calloc (total_rows, sizeof (line_t));
 
       int p    = MOD (term_start + prev_nrow, prev_total_rows);  // previous row
       int pend = MOD (term_start + top_row  , prev_total_rows);
@@ -646,7 +646,7 @@
 
       // sever bottommost line
       {
-        line_t &l = ROW(row2 - 1);
+        line_t &l = ROW(row2);
         l.is_longer (0);
         l.touch ();
       }
@@ -736,11 +736,19 @@
       // use a simple and robust scrolling algorithm, this
       // part of scr_scroll_text is not time-critical.
 
+      // sever line above scroll region
+      if (row1)
+        {
+          line_t &l = ROW(row1 - 1);
+          l.is_longer (0);
+          l.touch ();
+        }
+
       int rows = row2 - row1 + 1;
 
       min_it (count, rows);
 
-      line_t *temp_buf = row_buf + total_rows;
+      line_t *temp_buf = rxvt_temp_buf<line_t> (rows);
 
       for (int row = 0; row < rows; row++)
         {
@@ -752,6 +760,13 @@
 
       for (int row = 0; row < rows; row++)
         ROW(row1 + row) = temp_buf [row];
+
+      // sever bottommost line
+      {
+        line_t &l = ROW(row2);
+        l.is_longer (0);
+        l.touch ();
+      }
     }
 
   return count;