Select current revision when showing the revision popup

Closes #12472

sao/src/tab.js

@@ -993,7 +993,13 @@
                 return this.screen.model.execute('history_revisions',
                     [ids], this.screen.context)
                     .then(revisions => {
-                        new Sao.Window.Revision(revisions, set_revision(revisions));
+                        const revision = this.screen.context._datetime;
+                        if (revision) {
+                            // Remove a millisecond as microseconds are truncated
+                            revision.add(-1, 'milliseconds');
+                        }
+                        new Sao.Window.Revision(
+                            revisions, revision, set_revision(revisions));
                     });
             });
         },

sao/src/window.js

@@ -1083,7 +1083,7 @@
     });
 
     Sao.Window.Revision = Sao.class_(Object, {
-        init: function(revisions, callback) {
+        init: function(revisions, revision, callback) {
             this.callback = callback;
             var dialog = new Sao.Dialog(
                     Sao.i18n.gettext('Revision'), '', 'lg');
@@ -1124,15 +1124,18 @@
                 value: null,
                 text: ''
             }));
-            for (let revision of revisions) {
-                var name = revision[2];
-                revision = revision[0];
+            for (let rev of revisions) {
+                var name = rev[2];
+                rev = rev[0];
                 this.select.append(jQuery('<option/>', {
-                    value: revision.valueOf(),
+                    value: rev.valueOf(),
                     text: Sao.common.format_datetime(
-                        date_format + ' ' + time_format, revision) + ' ' + name,
+                        date_format + ' ' + time_format, rev) + ' ' + name,
                 }));
             }
+            if (revision) {
+                this.select.val(revision.valueOf());
+            }
             this.el.modal('show');
             this.el.on('hidden.bs.modal', function(event) {
                 jQuery(this).remove();