--- rxvt-unicode/src/screen.C	2011/05/30 18:39:04	1.384
+++ rxvt-unicode/src/screen.C	2011/11/01 00:04:46	1.395
@@ -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);
@@ -640,24 +640,38 @@
       && row1 == 0
       && (current_screen == PRIMARY || option (Opt_secondaryScroll)))
     {
-      top_row = max (top_row - count, -saveLines);
+      min_it (count, total_rows - (nrow - (row2 + 1)));
 
-      // scroll everything up 'count' lines
-      term_start = (term_start + count) % total_rows;
+      top_row = max (top_row - count, -saveLines);
 
       // sever bottommost line
       {
-        line_t &l = ROW(row2 - count);
+        line_t &l = ROW(row2);
         l.is_longer (0);
         l.touch ();
       }
 
+      // scroll everything up 'count' lines
+      term_start = (term_start + count) % total_rows;
+
+      // now copy lines below the scroll region bottom to the
+      // bottom of the screen again, so they look as if they
+      // hadn't moved.
+      for (int i = nrow; --i > row2; )
+        {
+          line_t &l1 = ROW(i - count);
+          line_t &l2 = ROW(i);
+
+          ::swap (l1, l2);
+          l2.touch ();
+        }
+
       // erase newly scrolled-in lines
       for (int i = count; i--; )
         {
-          line_t &l = ROW(nrow - 1 - i);
+          line_t &l = ROW(row2 - i);
 
-          // optimize if already cleared, can be significant on slow machines
+          // optimise if already cleared, can be significant on slow machines
           // could be rolled into scr_blank_screen_mem
           if (l.r && l.l < ncol - 1 && !((l.r[l.l + 1] ^ rstyle) & (RS_fgMask | RS_bgMask)))
             {
@@ -669,18 +683,6 @@
             scr_blank_screen_mem (l, rstyle);
         }
 
-      // now copy lines below the scroll region bottom to the
-      // bottom of the screen again, so they look as if they
-      // hadn't moved.
-      for (int i = nrow; --i > row2; )
-        {
-          line_t &l1 = ROW(i - count);
-          line_t &l2 = ROW(i);
-
-          ::swap (l1, l2);
-          l2.touch ();
-        }
-
       // move and/or clear selection, if any
       if (selection.op && current_screen == selection.screen)
         {
@@ -734,11 +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++)
         {
@@ -750,6 +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;
@@ -2548,7 +2565,7 @@
         XSetWindowBackgroundPixmap (dpy, scrollBar.win, ParentRelative);
       else
         XSetWindowBackground (dpy, scrollBar.win, pix_colors[Color_border]);
-      scrollBar.state = STATE_IDLE;
+      scrollBar.state = SB_STATE_IDLE;
       scrollBar.show (0);
     }
 
@@ -2702,7 +2719,7 @@
       || (check_more == 4     /* screen width change */
           && (selection.beg.row != selection.end.row
               || selection.end.col > ncol)))
-    CLEAR_SELECTION ();
+    CLEAR_ALL_SELECTION ();
 }
 
 /* ------------------------------------------------------------------------- */