diff --git a/src/testdir/test_window_cmd.vim b/src/testdir/test_window_cmd.vim
index 68c44a0..a55567f 100644
--- a/src/testdir/test_window_cmd.vim
+++ b/src/testdir/test_window_cmd.vim
@@ -1379,13 +1379,17 @@
 
   if has('timers')
     " check size is fixed in Insert mode
+    func s:CheckSize(timer) abort
+      call win_execute(win_getid(2), 'wincmd _')
+      call assert_equal(0, winheight(0))
+      call feedkeys(" \<Esc>", 't!')
+    endfunc
     new
-    call timer_start(100, {_ -> win_execute(win_getid(2), 'wincmd _')})
-    call timer_start(200, {_ -> assert_equal(0, winheight(0))})
-    call timer_start(300, {_ -> feedkeys(" \<Esc>", 't!')})
+    call timer_start(100, function('s:CheckSize'))
     call feedkeys('a', 'tx!')
     call assert_equal(1, winheight(0))
     bwipe!
+    delfunc s:CheckSize
   endif
 
   set winminwidth& winminheight&
diff --git a/src/version.c b/src/version.c
index 09bbb91..ac574d5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3789,
+/**/
     3788,
 /**/
     3787,