From d1291774fd493b6a559636d8955a368e2c8de51f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Krier?= <ced@b2ck.com>
Date: Mon, 25 Apr 2022 23:20:57 +0200
Subject: [PATCH] Compute next/previous record to set button state

The position is not enough to determine if the button will change the current
record. Also the position can be a list for the tree.

issue11413
review405241002
---
 src/screen.js | 38 ++++++++++++++++++++++++++++----------
 src/tab.js    |  4 ++--
 2 files changed, 30 insertions(+), 12 deletions(-)

diff --git a/src/screen.js b/src/screen.js
index ea87cdfc71..8255c24787 100644
--- a/src/screen.js
+++ b/src/screen.js
@@ -1355,10 +1355,8 @@
                     }
                 }));
         },
-        display_next: function() {
+        _get_next_record: function() {
             var view = this.current_view;
-            view.set_value();
-            this.set_cursor(false, false);
             if (~['tree', 'form', 'list-form'].indexOf(view.view_type) &&
                     this.current_record && this.current_record.group) {
                 var group = this.current_record.group;
@@ -1377,17 +1375,26 @@
                         break;
                     }
                 }
-                this.current_record = record;
+                return record;
             } else {
-                this.current_record = this.group[0];
+                return this.group[0];
             }
-            this.set_cursor(false, false);
-            return view.display();
         },
-        display_previous: function() {
+        has_next: function() {
+            var next_record = this._get_next_record();
+            return next_record &&
+                (next_record !== this.current_record);
+        },
+        display_next: function() {
             var view = this.current_view;
             view.set_value();
             this.set_cursor(false, false);
+            this.current_record = this._get_next_record();
+            this.set_cursor(false, false);
+            return view.display();
+        },
+        _get_previous_record: function() {
+            var view = this.current_view;
             if (~['tree', 'form', 'list-form'].indexOf(view.view_type) &&
                     this.current_record && this.current_record.group) {
                 var group = this.current_record.group;
@@ -1406,10 +1413,21 @@
                         break;
                     }
                 }
-                this.current_record = record;
+                return record;
             } else {
-                this.current_record = this.group[0];
+                return this.group[0];
             }
+        },
+        has_previous: function() {
+            var previous_record = this._get_previous_record();
+            return previous_record &&
+                (previous_record !== this.current_record);
+        },
+        display_previous: function() {
+            var view = this.current_view;
+            view.set_value();
+            this.set_cursor(false, false);
+            this.current_record = this._get_previous_record();
             this.set_cursor(false, false);
             return view.display();
         },
diff --git a/src/tab.js b/src/tab.js
index f9186bc9c0..ff92de14f8 100644
--- a/src/tab.js
+++ b/src/tab.js
@@ -1487,8 +1487,8 @@
             }
             set_sensitive('switch_', this.screen.number_of_views > 1);
             set_sensitive('delete_', this.screen.deletable);
-            set_sensitive('previous', position > (this.screen.offset + 1));
-            set_sensitive('next', position < size);
+            set_sensitive('previous', this.screen.has_previous());
+            set_sensitive('next', this.screen.has_next());
 
             var msg;
             if (size < max_size) {