[vte] Revert "Bug 591648 - Don't clear the screen when switching to the alternate screen"

[Behdad Esfahbod <behdad src gnome org>]

commit 9120f5ebfb9da0d74698f187ebb3046877b48c19
Author: Behdad Esfahbod <behdad behdad org>
Date:   Sun Nov 8 12:04:16 2009 -0500

    Revert "Bug 591648 - Don't clear the screen when switching to the alternate screen"
    
    This reverts commit c6d9bf421f12911298d921314ced64661f6b63bd.
    That commit introduced issues with less.   Xterm doesn't have those
    problems.  Need to figure out what's going on  before committing this
    again.

 src/vteseq.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/src/vteseq.c b/src/vteseq.c
index 4d533b3..370077a 100644
--- a/src/vteseq.c
+++ b/src/vteseq.c
@@ -821,6 +821,12 @@ vte_sequence_handler_decset_internal(VteTerminal *terminal,
 	case 47:
 	case 1047:
 	case 1049:
+		/* Clear the alternate screen if we're switching
+		 * to it, and home the cursor. */
+		if (set) {
+			_vte_terminal_clear_screen (terminal);
+			_vte_terminal_home_cursor (terminal);
+		}
 		/* Reset scrollbars and repaint everything. */
 		terminal->adjustment->value =
 			terminal->pvt->screen->scroll_delta;