Fixes #3320 - Problem with Adding new Rows in Tree-Select.

app/assets/javascripts/app/controllers/_ui_element/object_manager_attribute.coffee

@@ -362,6 +362,20 @@ class App.UiElement.object_manager_attribute extends App.UiElement.ApplicationUi
       for subChild in child.children
         @buildRow(element, subChild, level + 1)
 
+  @findParent: (element, level, mode) ->
+    parent = $(element).closest('tr')
+    parent.nextAll().each(->
+      if parseInt($(@).find('.js-key').attr('level')) > level && mode is 'first'
+        parent = $(@)
+        return true
+      if parseInt($(@).find('.js-key').attr('level')) >= level && mode is 'last'
+        parent = $(@)
+        return true
+      return false
+    )
+
+    return parent
+
   @tree_select: (item, localParams, params, attribute) ->
     params.data_option ||= {}
     params.data_option.options ||= []
@@ -374,16 +388,16 @@ class App.UiElement.object_manager_attribute extends App.UiElement.ApplicationUi
     item.on('click', '.js-addRow', (e) =>
       e.stopPropagation()
       e.preventDefault()
-      addRow = $(e.currentTarget).closest('tr')
-      level  = parseInt(addRow.find('.js-key').attr('level'))
+      level  = parseInt($(e.currentTarget).closest('tr').find('.js-key').attr('level'))
+      addRow = @findParent(e.currentTarget, level, 'first')
       @buildRow(item, {}, level, addRow)
     )
 
     item.on('click', '.js-addChild', (e) =>
       e.stopPropagation()
       e.preventDefault()
-      addRow = $(e.currentTarget).closest('tr')
-      level  = parseInt(addRow.find('.js-key').attr('level')) + 1
+      level  = parseInt($(e.currentTarget).closest('tr').find('.js-key').attr('level')) + 1
+      addRow = @findParent(e.currentTarget, level, 'last')
       @buildRow(item, {}, level, addRow)
     )
 

spec/system/system/object_manager_spec.rb

@@ -0,0 +1,68 @@
+require 'rails_helper'
+
+# https://github.com/zammad/zammad/issues/266
+RSpec.describe 'Admin Panel > Objects', type: :system, authenticated_as: true do
+  before do
+    visit '/#system/object_manager'
+  end
+
+  it 'verifies option creation order of new tree select options' do
+
+    # create new field
+    page.find('.js-new').click
+
+    # set meta information
+    fill_in 'Name', with: 'tree1'
+    fill_in 'Display', with: 'tree1'
+    page.find('select[name=data_type]').select('Tree Select')
+
+    # create 3 childs
+    first_add_child = page.first('div.js-addChild')
+    first_add_child.click
+    first_add_child.click
+    first_add_child.click
+
+    # create 1 top level node sibling
+    page.first('div.js-addRow').click
+
+    # create 3 childs for the new top level node
+    page.all('div.js-addChild').last.click
+    page.all('div.js-addChild').last.click
+    page.all('div.js-addChild').last.click
+
+    # create new top level nodes by first and second top level node
+    add_rows = page.all('div.js-addRow')
+    add_rows[0].click
+    add_rows[4].click
+
+    # add numbers to all inputs to verify order in config later
+    number = 1
+    page.all('input.js-key').each do |input|
+      input.send_keys(number)
+      number += 1
+    end
+
+    page.find('.js-submit').click
+    expected_data_options = { 'options'    =>
+                                              [{ 'name'     => '1',
+                                                 'value'    => '1',
+                                                 'children' => [{ 'name' => '2', 'value' => '1::2' }, { 'name' => '3', 'value' => '1::3' }, { 'name' => '4', 'value' => '1::4' }] },
+                                               { 'name' => '5', 'value' => '5' },
+                                               { 'name'     => '6',
+                                                 'value'    => '6',
+                                                 'children' =>
+                                                               [{ 'name'     => '7',
+                                                                  'value'    => '6::7',
+                                                                  'children' => [{ 'name' => '8', 'value' => '6::7::8', 'children' => [{ 'name' => '9', 'value' => '6::7::8::9' }] }] }] },
+                                               { 'name' => '10', 'value' => '10' }],
+                              'default'    => '',
+                              'null'       => true,
+                              'relation'   => '',
+                              'nulloption' => true,
+                              'maxlength'  => 255 }
+
+    await_empty_ajax_queue
+
+    expect(ObjectManager::Attribute.last.data_option).to eq(expected_data_options)
+  end
+end