patch 8.0.1449: slow redrawing with DirectX commit https://github.com/vim/vim/commit/a338adcf222b6a24e26ea5ae6a2ad27f914acb38 Author: Bram Moolenaar <Bram@vim.org> Date: Wed Jan 31 20:51:47 2018 +0100 patch 8.0.1449: slow redrawing with DirectX Problem: Slow redrawing with DirectX. Solution: Avoid calling gui_mch_flush() unnecessarily, especially when updating the cursor. (Ken Takata, closes #2560)

--- a/src/message.c
+++ b/src/message.c
@@ -2316,7 +2316,9 @@ msg_scroll_up(void)
 	gui_undraw_cursor();
 #endif
     /* scrolling up always works */
+    mch_disable_flush();
     screen_del_lines(0, 0, 1, (int)Rows, TRUE, 0, NULL);
+    mch_enable_flush();
 
     if (!can_clear((char_u *)" "))
     {