diff --git a/app/assets/javascripts/angular/config/work-packages-config.js b/app/assets/javascripts/angular/config/work-packages-config.js
index db06be72ff..6e8e69bc1e 100644
--- a/app/assets/javascripts/angular/config/work-packages-config.js
+++ b/app/assets/javascripts/angular/config/work-packages-config.js
@@ -31,29 +31,29 @@ angular.module('openproject.workPackages.config')
 .constant('INITIALLY_SELECTED_COLUMNS', ['id', 'project', 'type', 'status', 'priority', 'subject', 'assigned_to_id', 'updated_at'])
 
 .constant('OPERATORS_AND_LABELS_BY_FILTER_TYPE', {
-  list: {'=':'label_equals','!':'label_not_equals'},
-  list_model: {'=':'label_equals','!':'label_not_equals'},
-  list_status: {'o':'label_open_work_packages','=':'label_equals','!':'label_not_equals','c':'label_closed_work_packages','*':'label_all'},
-  list_optional: {'=':'label_equals','!':'label_not_equals','!*':'label_none','*':'label_all'},
-  list_subprojects: {'*':'label_all','!*':'label_none','=':'label_equals'},
-  date: {'<t+':'label_in_less_than','>t+':'label_in_more_than','t+':'label_in','t':'label_today','w':'label_this_week','>t-':'label_less_than_ago','<t-':'label_more_than_ago','t-':'label_ago'},
-  date_past: {'>t-':'label_less_than_ago','<t-':'label_more_than_ago','t-':'label_ago','t':'label_today','w':'label_this_week'},
-  string: {'=':'label_equals','~':'label_contains','!':'label_not_equals','!~':"label_not_contains"},
-  text: {'~':'label_contains','!~':"label_not_contains"},
-  integer: {'=':'label_equals','>=':'label_greater_or_equal','<=':'label_less_or_equal','!*':'label_none','*':'label_all'}
+  list: [['=', 'label_equals'], ['!', 'label_not_equals']],
+  list_model: [['=', 'label_equals'], ['!', 'label_not_equals']],
+  list_status: [['o', 'label_open_work_packages'], ['=', 'label_equals'], ['!', 'label_not_equals'], ['c', 'label_closed_work_packages'], ['*', 'label_all']],
+  list_optional: [['=', 'label_equals'], ['!', 'label_not_equals'], ['!*', 'label_none'], ['*', 'label_all']],
+  list_subprojects: [['*', 'label_all'], ['!*', 'label_none'], ['=', 'label_equals']],
+  date: [['<t+', 'label_in_less_than'], ['>t+', 'label_in_more_than'], ['t+', 'label_in'], ['t', 'label_today'], ['w', 'label_this_week'], ['>t-', 'label_less_than_ago'], ['<t-', 'label_more_than_ago'], ['t-', 'label_ago']],
+  date_past: [['>t-', 'label_less_than_ago'], ['<t-', 'label_more_than_ago'], ['t-', 'label_ago'], ['t', 'label_today'], ['w', 'label_this_week']],
+  string: [['=', 'label_equals'], ['~', 'label_contains'], ['!', 'label_not_equals'], ['!~', 'label_not_contains']],
+  text: [['~', 'label_contains'], ['!~', 'label_not_contains']],
+  integer: [['=', 'label_equals'], ['>=', 'label_greater_or_equal'], ['<=', 'label_less_or_equal'], ['!*', 'label_none'], ['*', 'label_all']]
 })
 
 .constant('AVAILABLE_WORK_PACKAGE_FILTERS', {
   status_id: { type: 'list_status', modelName: 'status' , order: 1, locale_name: 'status' },
   type_id: { type: 'list_model', modelName: 'type', order: 2, locale_name: 'type' },
   priority_id: { type: 'list_model', modelName: 'priority', order: 3, locale_name: 'priority'},
-  assigned_to_id: { type: 'list_model', modelName: 'user' , order: 4, locale_name: 'assigned_to' },
+  assigned_to_id: { type: 'list_optional', modelName: 'user' , order: 4, locale_name: 'assigned_to' },
   author_id: { type: 'list_model', modelName: 'user' , order: 5, locale_name: 'author' },
   watcher_id: {type: 'list_model', modelName: 'user', order: 6, locale_name: 'watcher'},
-  responsible_id: {type: 'list_model', modelName: 'user', order: 6, locale_name: 'responsible'},
-  fixed_version_id: {type: 'list_model', modelName: 'version', order: 7, locale_name: 'fixed_version'},
-  member_of_group: {type: 'list_model', modelName: 'group', order: 8, locale_name: 'member_of_group'},
-  assigned_to_role: {type: 'list_model', modelName: 'role', order: 9, locale_name: 'assigned_to_role'},
+  responsible_id: {type: 'list_optional', modelName: 'user', order: 6, locale_name: 'responsible'},
+  fixed_version_id: {type: 'list_optional', modelName: 'version', order: 7, locale_name: 'fixed_version'},
+  member_of_group: {type: 'list_optional', modelName: 'group', order: 8, locale_name: 'member_of_group'},
+  assigned_to_role: {type: 'list_optional', modelName: 'role', order: 9, locale_name: 'assigned_to_role'},
   subject: { type: 'text', order: 10, locale_name: 'subject' },
   created_at: { type: 'date_past', order: 11, locale_name: 'created_at' },
   updated_at: { type: 'date_past', order: 12, locale_name: 'updated_at' },
@@ -62,7 +62,7 @@ angular.module('openproject.workPackages.config')
   estimated_hours: { type: 'integer', order: 15, locale_name: 'estimated_hours' },
   done_ratio: { type: 'integer', order: 16, locale_name: 'done_ratio' },
   project_id: { type: 'list_model', modelName: 'project', order: 17, locale_name: 'project' },
-  subproject_id: { type: 'list_model', modelName: 'sub_project', order: 18, locale_name: 'subproject' },
+  subproject_id: { type: 'list_subprojects', modelName: 'sub_project', order: 18, locale_name: 'subproject' },
 })
 
 .constant('DEFAULT_SORT_CRITERIA', 'parent:desc')
diff --git a/public/templates/work_packages/query_filters.html b/public/templates/work_packages/query_filters.html
index 786449d4e3..36898b90de 100644
--- a/public/templates/work_packages/query_filters.html
+++ b/public/templates/work_packages/query_filters.html
@@ -41,7 +41,7 @@
                             class="select-small to-validate"
                             id="operators-{{filter.name}}"
                             name="op[{{filter.name}}]"
-                            ng-options="operator as I18n.t('js.' + label) for (operator, label) in operatorsAndLabelsByFilterType[filter.type]"
+                            ng-options="operator[0] as I18n.t('js.' + operator[1]) for operator in operatorsAndLabelsByFilterType[filter.type]"
                             ng-model="filter.operator"
                             style="vertical-align: top;"
                             ng-disabled="isLoading">