diff --git a/app/models/project.rb b/app/models/project.rb
index 3f3e216..a25513b 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -995,15 +995,15 @@ class Project < ActiveRecord::Base
 
   # Returns the systemwide active activities merged with the project specific overrides
   def system_activities_and_project_overrides(include_inactive=false)
-    if include_inactive
-      return TimeEntryActivity.shared.
-        where("id NOT IN (?)", self.time_entry_activities.collect(&:parent_id)).all +
-        self.time_entry_activities
-    else
-      return TimeEntryActivity.shared.active.
-        where("id NOT IN (?)", self.time_entry_activities.collect(&:parent_id)).all +
-        self.time_entry_activities.active
+    t = TimeEntryActivity.table_name
+    scope = TimeEntryActivity.where(
+      "(#{t}.project_id IS NULL AND #{t}.id NOT IN (?)) OR (#{t}.project_id = ?)",
+      time_entry_activities.map(&:parent_id), id
+    )
+    unless include_inactive
+      scope = scope.active
     end
+    scope
   end
 
   # Archives subprojects recursively
diff --git a/test/unit/project_test.rb b/test/unit/project_test.rb
index 7a2817d..0dc3a54 100644
--- a/test/unit/project_test.rb
+++ b/test/unit/project_test.rb
@@ -730,6 +730,7 @@ class ProjectTest < ActiveSupport::TestCase
   def test_activities_should_use_the_system_activities
     project = Project.find(1)
     assert_equal project.activities, TimeEntryActivity.where(:active => true).all
+    assert_kind_of ActiveRecord::Relation, project.activities
   end
 
 
@@ -739,6 +740,7 @@ class ProjectTest < ActiveSupport::TestCase
     assert overridden_activity.save!
 
     assert project.activities.include?(overridden_activity), "Project specific Activity not found"
+    assert_kind_of ActiveRecord::Relation, project.activities
   end
 
   def test_activities_should_not_include_the_inactive_project_specific_activities