diff --git a/app/models/principal.rb b/app/models/principal.rb
index d7814f595..77fe19fe0 100644
--- a/app/models/principal.rb
+++ b/app/models/principal.rb
@@ -33,6 +33,16 @@ class Principal < ActiveRecord::Base
     }
   }
 
+  # Principals that are members of a collection of projects
+  named_scope :member_of, lambda {|projects|
+    if projects.empty?
+      {:conditions => "1=0"}
+    else
+      ids = projects.map(&:id)
+      {:conditions => ["#{Principal.table_name}.status = 1 AND #{Principal.table_name}.id IN (SELECT DISTINCT user_id FROM #{Member.table_name} WHERE project_id IN (?))", ids]}
+    end
+  }
+
   before_create :set_default_empty_values
 
   def name(formatter = nil)
diff --git a/app/models/query.rb b/app/models/query.rb
index 1cfa952ff..84ab868ff 100644
--- a/app/models/query.rb
+++ b/app/models/query.rb
@@ -232,11 +232,18 @@ class Query < ActiveRecord::Base
     principals = []
     if project
       principals += project.principals.sort
+      unless project.leaf?
+        subprojects = project.descendants.visible.all
+        if subprojects.any?
+          @available_filters["subproject_id"] = { :type => :list_subprojects, :order => 13, :values => subprojects.collect{|s| [s.name, s.id.to_s] } }
+          principals += Principal.member_of(subprojects)
+        end
+      end
     else
       all_projects = Project.visible.all
       if all_projects.any?
         # members of visible projects
-        principals += Principal.active.find(:all, :conditions => ["#{User.table_name}.id IN (SELECT DISTINCT user_id FROM members WHERE project_id IN (?))", all_projects.collect(&:id)]).sort
+        principals += Principal.member_of(all_projects)
 
         # project filter
         project_values = []
@@ -250,6 +257,8 @@ class Query < ActiveRecord::Base
         @available_filters["project_id"] = { :type => :list, :order => 1, :values => project_values} unless project_values.empty?
       end
     end
+    principals.uniq!
+    principals.sort!
     users = principals.select {|p| p.is_a?(User)}
 
     assigned_to_values = []
@@ -282,12 +291,6 @@ class Query < ActiveRecord::Base
       unless versions.empty?
         @available_filters["fixed_version_id"] = { :type => :list_optional, :order => 7, :values => versions.sort.collect{|s| ["#{s.project.name} - #{s.name}", s.id.to_s] } }
       end
-      unless project.leaf?
-        subprojects = project.descendants.visible.all
-        unless subprojects.empty?
-          @available_filters["subproject_id"] = { :type => :list_subprojects, :order => 13, :values => subprojects.collect{|s| [s.name, s.id.to_s] } }
-        end
-      end
       add_custom_fields_filters(project.all_issue_custom_fields)
     else
       # global filters for cross project issue list
diff --git a/test/unit/principal_test.rb b/test/unit/principal_test.rb
index a3230f1c6..694f7e027 100644
--- a/test/unit/principal_test.rb
+++ b/test/unit/principal_test.rb
@@ -27,6 +27,11 @@ class PrincipalTest < ActiveSupport::TestCase
     assert_nil result.detect {|p| p.is_a?(AnonymousUser)}
   end
 
+  def test_member_of_scope_should_return_the_union_of_all_members
+    projects = Project.find_all_by_id(1, 2)
+    assert_equal projects.map(&:principals).flatten.sort, Principal.member_of(projects).sort
+  end
+
   context "#like" do
     setup do
       Principal.generate!(:login => 'login')
diff --git a/test/unit/query_test.rb b/test/unit/query_test.rb
index ca5bf9175..52e29de7e 100644
--- a/test/unit/query_test.rb
+++ b/test/unit/query_test.rb
@@ -766,6 +766,19 @@ class QueryTest < ActiveSupport::TestCase
       assert users[:values].map{|u|u[1]}.include?("3")
     end
 
+    should "include users of subprojects" do
+      user1 = User.generate_with_protected!
+      user2 = User.generate_with_protected!
+      project = Project.find(1)
+      Member.create!(:principal => user1, :project => project.children.visible.first, :role_ids => [1])
+      @query.project = project
+
+      users = @query.available_filters["assigned_to_id"]
+      assert_not_nil users
+      assert users[:values].map{|u|u[1]}.include?(user1.id.to_s)
+      assert !users[:values].map{|u|u[1]}.include?(user2.id.to_s)
+    end
+
     should "include visible projects in cross-project view" do
       projects = @query.available_filters["project_id"]
       assert_not_nil projects