diff --git a/src/testdir/test_visual.vim b/src/testdir/test_visual.vim
index a187aa8..72f5388 100644
--- a/src/testdir/test_visual.vim
+++ b/src/testdir/test_visual.vim
@@ -1318,5 +1318,15 @@
   bwipe!
 endfunc
 
+" this was causing an ml_get error
+func Test_visual_exchange_windows()
+  enew!
+  new
+  call setline(1, ['foo', 'bar'])
+  exe "normal G\<C-V>gg\<C-W>\<C-X>OO\<Esc>"
+  bwipe!
+  bwipe!
+endfunc
+
 
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index 54a9ebe..e32abbb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4154,
+/**/
     4153,
 /**/
     4152,
diff --git a/src/window.c b/src/window.c
index 05e85ba..7425727 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1691,6 +1691,11 @@
 
     (void)win_comp_pos();		// recompute window positions
 
+    if (wp->w_buffer != curbuf)
+	reset_VIsual_and_resel();
+    else if (VIsual_active)
+	wp->w_cursor = curwin->w_cursor;
+
     win_enter(wp, TRUE);
     redraw_all_later(NOT_VALID);
 }
@@ -5332,7 +5337,7 @@
 win_alloc_lines(win_T *wp)
 {
     wp->w_lines_valid = 0;
-    wp->w_lines = ALLOC_CLEAR_MULT(wline_T, Rows );
+    wp->w_lines = ALLOC_CLEAR_MULT(wline_T, Rows);
     if (wp->w_lines == NULL)
 	return FAIL;
     return OK;