patch 8.1.2363: ml_get error when accessing Visual area in 'statusline'

Problem:    ml_get error when accessing Visual area in 'statusline'.
Solution:   Disable Visual mode when using another window. (closes #5278)
diff --git a/src/buffer.c b/src/buffer.c
index cba84c6..3b50c89 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -3979,6 +3979,7 @@
 #ifdef FEAT_EVAL
     win_T	*save_curwin;
     buf_T	*save_curbuf;
+    int		save_VIsual_active;
 #endif
     int		empty_line;
     colnr_T	virtcol;
@@ -4368,13 +4369,18 @@
 
 	    save_curbuf = curbuf;
 	    save_curwin = curwin;
+	    save_VIsual_active = VIsual_active;
 	    curwin = wp;
 	    curbuf = wp->w_buffer;
+	    // Visual mode is only valid in the current window.
+	    if (curwin != save_curwin)
+		VIsual_active = FALSE;
 
 	    str = eval_to_string_safe(p, &t, use_sandbox);
 
 	    curwin = save_curwin;
 	    curbuf = save_curbuf;
+	    VIsual_active = save_VIsual_active;
 	    do_unlet((char_u *)"g:actual_curbuf", TRUE);
 	    do_unlet((char_u *)"g:actual_curwin", TRUE);
 
diff --git a/src/testdir/test_statusline.vim b/src/testdir/test_statusline.vim
index e1830d0..af05be5 100644
--- a/src/testdir/test_statusline.vim
+++ b/src/testdir/test_statusline.vim
@@ -368,3 +368,25 @@
   set laststatus&
   set splitbelow&
 endfunc
+
+func Test_statusline_visual()
+  func CallWordcount()
+    call wordcount()
+  endfunc
+  new x1
+  setl statusline=count=%{CallWordcount()}
+  " buffer must not be empty
+  call setline(1, 'hello')
+
+  " window with more lines than x1
+  new x2
+  call setline(1, range(10))
+  $
+  " Visual mode in line below liast line in x1 should not give ml_get error
+  call feedkeys("\<C-V>", "xt")
+  redraw
+
+  delfunc CallWordcount
+  bwipe! x1
+  bwipe! x2
+endfunc
diff --git a/src/version.c b/src/version.c
index 5833f38..1bb77a1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -738,6 +738,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2363,
+/**/
     2362,
 /**/
     2361,