diff --git a/src/eval.c b/src/eval.c
index 9313c27..ec34ef1 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -772,7 +772,7 @@
     return rettv.vval.v_list;
 }
 
-#ifdef FEAT_FOLDING
+#if defined(FEAT_FOLDING) || defined(PROTO)
 /*
  * Evaluate "arg", which is 'foldexpr'.
  * Note: caller must set "curwin" to match "arg".
@@ -780,14 +780,19 @@
  * give error messages.
  */
     int
-eval_foldexpr(char_u *arg, int *cp)
+eval_foldexpr(win_T *wp, int *cp)
 {
+    char_u	*arg;
     typval_T	tv;
     varnumber_T	retval;
     char_u	*s;
+    sctx_T	saved_sctx = current_sctx;
     int		use_sandbox = was_set_insecurely((char_u *)"foldexpr",
 								   OPT_LOCAL);
 
+    arg = wp->w_p_fde;
+    current_sctx = wp->w_p_script_ctx[WV_FDE];
+
     ++emsg_off;
     if (use_sandbox)
 	++sandbox;
@@ -818,6 +823,7 @@
 	--sandbox;
     --textwinlock;
     clear_evalarg(&EVALARG_EVALUATE, NULL);
+    current_sctx = saved_sctx;
 
     return (int)retval;
 }
diff --git a/src/fold.c b/src/fold.c
index f314d7a..2a45d21 100644
--- a/src/fold.c
+++ b/src/fold.c
@@ -3307,7 +3307,7 @@
     // KeyTyped may be reset to 0 when calling a function which invokes
     // do_cmdline().  To make 'foldopen' work correctly restore KeyTyped.
     save_keytyped = KeyTyped;
-    n = eval_foldexpr(flp->wp->w_p_fde, &c);
+    n = eval_foldexpr(flp->wp, &c);
     KeyTyped = save_keytyped;
 
     switch (c)
diff --git a/src/option.c b/src/option.c
index 2ec6ed5..4cc6142 100644
--- a/src/option.c
+++ b/src/option.c
@@ -2604,7 +2604,13 @@
 	if (indir & PV_BUF)
 	    curbuf->b_p_script_ctx[indir & PV_MASK] = new_script_ctx;
 	else if (indir & PV_WIN)
+	{
 	    curwin->w_p_script_ctx[indir & PV_MASK] = new_script_ctx;
+	    if (both)
+		// also setting the "all buffers" value
+		curwin->w_allbuf_opt.wo_script_ctx[indir & PV_MASK] =
+								new_script_ctx;
+	}
     }
 }
 
diff --git a/src/proto/eval.pro b/src/proto/eval.pro
index ac4a51c..b0e94a0 100644
--- a/src/proto/eval.pro
+++ b/src/proto/eval.pro
@@ -18,11 +18,9 @@
 varnumber_T eval_to_number(char_u *expr);
 typval_T *eval_expr(char_u *arg, exarg_T *eap);
 int call_vim_function(char_u *func, int argc, typval_T *argv, typval_T *rettv);
-varnumber_T call_func_retnr(char_u *func, int argc, typval_T *argv);
-int call_func_noret(char_u *func, int argc, typval_T *argv);
 void *call_func_retstr(char_u *func, int argc, typval_T *argv);
 void *call_func_retlist(char_u *func, int argc, typval_T *argv);
-int eval_foldexpr(char_u *arg, int *cp);
+int eval_foldexpr(win_T *wp, int *cp);
 char_u *get_lval(char_u *name, typval_T *rettv, lval_T *lp, int unlet, int skip, int flags, int fne_flags);
 void clear_lval(lval_T *lp);
 void set_var_lval(lval_T *lp, char_u *endp, typval_T *rettv, int copy, int flags, char_u *op, int var_idx);
diff --git a/src/structs.h b/src/structs.h
index f733268..e2f1de9 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -3695,6 +3695,8 @@
      */
     winopt_T	w_onebuf_opt;
     winopt_T	w_allbuf_opt;
+    // transform a pointer to a "onebuf" option into a "allbuf" option
+#define GLOBAL_WO(p)	((char *)p + sizeof(winopt_T))
 
     // A few options have local flags for P_INSECURE.
 #ifdef FEAT_STL_OPT
@@ -3718,9 +3720,6 @@
     int		w_briopt_list;      // additional indent for lists
 #endif
 
-    // transform a pointer to a "onebuf" option into a "allbuf" option
-#define GLOBAL_WO(p)	((char *)p + sizeof(winopt_T))
-
     long	w_scbind_pos;
 
 #ifdef FEAT_EVAL
diff --git a/src/testdir/test_vim9_import.vim b/src/testdir/test_vim9_import.vim
index 6e61d07..6ecea56 100644
--- a/src/testdir/test_vim9_import.vim
+++ b/src/testdir/test_vim9_import.vim
@@ -673,6 +673,45 @@
   &rtp = save_rtp
 enddef
 
+def Test_use_autoload_import_in_fold_expression()
+  mkdir('Xdir/autoload', 'p')
+  var save_rtp = &rtp
+  exe 'set rtp^=' .. getcwd() .. '/Xdir'
+
+  var lines =<< trim END
+      vim9script
+      export def Expr(): string
+        return getline(v:lnum) =~ '^#' ? '>1' : '1'
+      enddef
+      g:fold_loaded = 'yes'
+  END
+  writefile(lines, 'Xdir/autoload/fold.vim')
+
+  lines =<< trim END
+      vim9script
+      import autoload 'fold.vim'
+      &foldexpr = 'fold.Expr()'
+      &foldmethod = 'expr'
+      &debug = 'throw'
+  END
+  new
+  setline(1, ['# one', 'text', '# two', 'text'])
+  g:fold_loaded = 'no'
+  CheckScriptSuccess(lines)
+  assert_equal('no', g:fold_loaded)
+  redraw
+  assert_equal('yes', g:fold_loaded)
+
+  # Check that script context of 'foldexpr' is copied to another buffer.
+  edit! otherfile
+  redraw
+
+  set foldexpr= foldmethod&
+  bwipe!
+  delete('Xdir', 'rf')
+  &rtp = save_rtp
+enddef
+
 def Test_export_fails()
   CheckScriptFailure(['export var some = 123'], 'E1042:')
   CheckScriptFailure(['vim9script', 'export var g:some'], 'E1022:')
diff --git a/src/version.c b/src/version.c
index 45ae6d5..a9a8323 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4173,
+/**/
     4172,
 /**/
     4171,