diff --git a/sao/src/common.js b/sao/src/common.js
index 709d1940a6..f6dff83cb5 100644
--- a/sao/src/common.js
+++ b/sao/src/common.js
@@ -3547,24 +3547,38 @@
 
     Sao.common.ErrorDialog = Sao.class_(Sao.common.UniqueDialog, {
         class_: 'error-dialog',
-        size: 'lg',
+        size: 'md',
         build_dialog: function(title, details, prm) {
             var dialog = Sao.common.ConcurrencyDialog._super.build_dialog.call(
                 this);
             dialog.add_title(Sao.i18n.gettext('Application Error'));
-            dialog.body.append(jQuery('<div/>', {
+            const alert_ = jQuery('<div/>', {
                 'class': 'alert alert-danger',
                 role: 'alert'
-            }).append(jQuery('<p/>')
-                .append(jQuery('<pre/>')
-                    .text(details)))
-                .append(jQuery('<p/>')
-                    .append(jQuery('<a/>', {
-                        'class': 'btn btn-link',
-                        href: Sao.config.bug_url,
-                        target: '_blank',
-                        rel: 'noreferrer noopener',
-                    }).text(Sao.i18n.gettext('Report Bug')))));
+            }).appendTo(dialog.body);
+            alert_.append(jQuery('<h4/>')
+                .text(title)
+                .css('white-space', 'pre-wrap'));
+            alert_.append(jQuery('<p/>').append(jQuery('<a/>', {
+                'class': 'btn btn-default',
+                role: 'button',
+                'data-toggle': 'collapse',
+                'data-target': '#error-detail',
+                'aria-expanded': false,
+                'aria-controls': '#error-detail',
+            }).text(Sao.i18n.gettext("Details"))));
+            alert_.append(jQuery('<p/>', {
+                'class': 'collapse',
+                id: 'error-detail',
+            }).append(jQuery('<pre/>', {
+                'class': 'pre-scrollable',
+            }).text(details)));
+            jQuery('<a/>', {
+                'class': 'btn btn-link',
+                href: Sao.config.bug_url,
+                target: '_blank',
+                rel: 'noreferrer noopener',
+            }).text(Sao.i18n.gettext('Report Bug')).appendTo(dialog.footer);
             jQuery('<button/>', {
                 'class': 'btn btn-primary',
                 'type': 'button',
diff --git a/tryton/tryton/common/common.py b/tryton/tryton/common/common.py
index a3c41c5f0a..6758f30057 100644
--- a/tryton/tryton/common/common.py
+++ b/tryton/tryton/common/common.py
@@ -844,7 +844,7 @@ class ErrorDialog(UniqueDialog):
         dialog = Gtk.MessageDialog(
             transient_for=parent, modal=True, destroy_with_parent=True,
             message_type=Gtk.MessageType.ERROR, buttons=Gtk.ButtonsType.NONE)
-        dialog.set_default_size(600, 400)
+        dialog.set_default_size(600, 200)
         dialog.set_position(Gtk.WindowPosition.CENTER)
 
         dialog.add_button(set_underline(_("Close")), Gtk.ResponseType.CANCEL)
@@ -859,6 +859,7 @@ class ErrorDialog(UniqueDialog):
         scrolledwindow.set_policy(
             Gtk.PolicyType.AUTOMATIC, Gtk.PolicyType.AUTOMATIC)
         scrolledwindow.set_shadow_type(Gtk.ShadowType.NONE)
+        scrolledwindow.set_min_content_height(300)
 
         viewport = Gtk.Viewport()
         viewport.set_shadow_type(Gtk.ShadowType.NONE)
@@ -870,8 +871,12 @@ class ErrorDialog(UniqueDialog):
 
         viewport.add(textview)
         scrolledwindow.add(viewport)
+        expander = Gtk.Expander()
+        expander.set_label(_("Details"))
+        expander.add(scrolledwindow)
+        expander.set_resize_toplevel(True)
         dialog.vbox.pack_start(
-            scrolledwindow, expand=True, fill=True, padding=0)
+            expander, expand=False, fill=True, padding=0)
 
         button_roundup = Gtk.LinkButton.new_with_label(
             CONFIG['bug.url'], _("Report Bug"))