Index: app/helpers/queries_helper.rb
===================================================================
--- app/helpers/queries_helper.rb	(revision 15590)
+++ app/helpers/queries_helper.rb	(working copy)
@@ -257,6 +257,8 @@
           tags << hidden_field_tag("v[#{field}][]", value, :id => nil)
         end
       end
+    else
+      tags << hidden_field_tag("f[]", "", :id => nil)
     end
     if query.column_names.present?
       query.column_names.each do |name|
Index: test/functional/issues_controller_test.rb
===================================================================
--- test/functional/issues_controller_test.rb	(revision 15590)
+++ test/functional/issues_controller_test.rb	(working copy)
@@ -488,6 +488,9 @@
 
       assert_select 'input[name=?][value=?]', 'sort', 'status'
     end
+
+    get :index, :project_id => 1, :set_filter => "1", :f => []
+    assert_select '#csv-export-form input[name=?][value=?]', 'f[]', ''
   end
 
   def test_index_csv