Allow the selection order to be preserved in the Select2 control to fix column ordering in data Import/Export. Fixes #3029

docs/en_US/release_notes.rst

@@ -9,6 +9,7 @@ for it.
 
 .. toctree::
 
+   release_notes_3_6
    release_notes_3_5
    release_notes_3_4
    release_notes_3_3

docs/en_US/release_notes_3_6.rst

@@ -0,0 +1,18 @@
+***********
+Version 3.6
+***********
+
+Release date: 2018-11-29
+
+This release contains a number of features and fixes reported since the release of pgAdmin4 3.5
+
+
+Features
+********
+
+
+
+Bug fixes
+*********
+
+| `Bug #3029 <https://redmine.postgresql.org/issues/3029>`_ - Allow the selection order to be preserved in the Select2 control to fix column ordering in data Import/Export.

web/pgadmin/static/js/backform.pgadmin.js

@@ -1781,8 +1781,29 @@ define([
         first_empty: true,
         multiple: false,
         emptyOptions: false,
+        preserveSelectionOrder: false,
       },
     }),
+
+    events: function() {
+      // Inherit all default events of InputControl
+      return _.extend({}, Backform.SelectControl.prototype.events, {
+        'select2:select': 'onSelect',
+      });
+    },
+
+    onSelect: function (evt) {
+      var sel2Options = this.field.get('select2');
+      if (sel2Options.multiple && sel2Options.preserveSelectionOrder) {
+        var element = evt.params.data.element;
+        var $element = $(element);
+
+        $element.detach();
+        $(this.$sel).append($element);
+        $(this.$sel).trigger('change');
+      }
+    },
+
     formatter: Select2Formatter,
     template: _.template([
       '<label class="<%=Backform.controlLabelClassName%>"><%=label%></label>',
@@ -1836,6 +1857,7 @@ define([
         first_empty: true,
         multiple: false,
         emptyOptions: false,
+        preserveSelectionOrder: false,
       });
 
       // Evaluate the disabled, visible, and required option

web/pgadmin/tools/import_export/static/js/import_export.js

@@ -174,6 +174,7 @@ Backform, commonUtils, supportedNodes
         allowClear: false,
         placeholder: gettext('Columns for importing...'),
         first_empty: false,
+        preserveSelectionOrder: true,
       },
       visible: 'importing',
       helpMessage: gettext('An optional list of columns to be copied. If no column list is specified, all columns of the table will be copied.'),
@@ -192,6 +193,7 @@ Backform, commonUtils, supportedNodes
         multiple: true,
         allowClear: true,
         placeholder: gettext('Colums for exporting...'),
+        preserveSelectionOrder: true,
       },
       visible: 'exporting',
       transform: function(rows) {