diff --git a/app/models/project.rb b/app/models/project.rb
index 295d3cb05..f58a14bae 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -393,6 +393,15 @@ class Project < ActiveRecord::Base
     end
   end
 
+  # Recalculates all lft and rgt values based on project names
+  # Unlike Project.rebuild!, these values are recalculated even if the tree "looks" valid
+  def self.rebuild_tree!
+    transaction do
+      update_all "lft = NULL, rgt = NULL"
+      rebuild!(false)
+    end
+  end
+
   # Returns an array of the trackers used by the project and its active sub projects
   def rolled_up_trackers
     @rolled_up_trackers ||=
diff --git a/test/unit/project_nested_set_test.rb b/test/unit/project_nested_set_test.rb
index 3bd37609b..b038f30ac 100644
--- a/test/unit/project_nested_set_test.rb
+++ b/test/unit/project_nested_set_test.rb
@@ -54,6 +54,15 @@ class ProjectNestedSetTest < ActiveSupport::TestCase
     assert_valid_nested_set
   end
 
+  def test_rebuild_tree_should_build_valid_tree_even_with_valid_lft_rgt_values
+    Project.update_all "name = 'YY'", {:id => @a.id }
+    # lft and rgt values are still valid (Project.rebuild! would not update anything)
+    # but projects are not ordered properly (YY is in the first place)
+
+    Project.rebuild_tree!
+    assert_valid_nested_set
+  end
+
   def test_moving_a_child_to_a_different_parent_should_keep_valid_tree
     assert_no_difference 'Project.count' do
       Project.find_by_name('B1').set_parent!(Project.find_by_name('A2'))