Did a bit of hacking to get grouping by custom values working again.

app/assets/javascripts/angular/directives/work_packages/work-package-column-directive.js

@@ -36,7 +36,8 @@ angular.module('openproject.workPackages.directives')
     scope: {
       workPackage: '=',
       column: '=',
-      displayType: '@'
+      displayType: '@',
+      displayEmpty: '='
     },
     templateUrl: '/templates/work_packages/work_package_column.html',
     link: function(scope, element, attributes) {
@@ -50,12 +51,12 @@ angular.module('openproject.workPackages.directives')
         if (scope.column.custom_field) {
           var custom_field = scope.column.custom_field;
 
-          scope.displayText = WorkPackagesHelper.getFormattedCustomValue(scope.workPackage, custom_field) || '';
+          scope.displayText = WorkPackagesHelper.getFormattedCustomValue(scope.workPackage, custom_field) || scope.displayEmpty || '';
         } else {
           // custom display types
           if (scope.column.name === 'done_ratio') scope.displayType = 'progress_bar';
 
-          scope.displayText = WorkPackagesHelper.getFormattedColumnData(scope.workPackage, scope.column) || '';
+          scope.displayText = WorkPackagesHelper.getFormattedColumnData(scope.workPackage, scope.column) || scope.displayEmpty || '';
         }
 
         // Example of how we can look to the provided meta data to format the column

app/assets/javascripts/angular/directives/work_packages/work-packages-options-directive.js

@@ -39,7 +39,7 @@ angular.module('openproject.workPackages.directives')
             return column.name;
           }).indexOf(groupBy);
 
-          scope.groupByColumn = scope.columns[groupByColumnIndex];
+          scope.groupByColumn = scope.groupableColumns[groupByColumnIndex];
           scope.updateBackUrl();
         }
       });

app/assets/javascripts/angular/helpers/components/work-packages-helper.js

@@ -31,7 +31,11 @@ angular.module('openproject.workPackages.helpers')
 .factory('WorkPackagesHelper', ['dateFilter', 'CustomFieldHelper', function(dateFilter, CustomFieldHelper) {
   var WorkPackagesHelper = {
     getRowObjectContent: function(object, option) {
-      var content = object[option];
+      if(CustomFieldHelper.isCustomFieldKey(option)){
+        var content = WorkPackagesHelper.getRawCustomValue(object, CustomFieldHelper.getCustomFieldId(option));
+      } else {
+        var content = object[option];
+      }
 
       switch(typeof(content)) {
         case 'object':
@@ -54,6 +58,20 @@ angular.module('openproject.workPackages.helpers')
       }
     },
 
+    getRawCustomValue: function(object, customFieldId) {
+      if (!object.custom_values) return null;
+
+      var customValue = object.custom_values.filter(function(customValue){
+        return customValue && customValue.custom_field_id === customFieldId;
+      }).first();
+
+      if (customValue) {
+        return customValue.value;
+      } else {
+        return '';
+      }
+    },
+
     getFormattedCustomValue: function(object, customField) {
       if (!object.custom_values) return null;
 

app/assets/javascripts/angular/models/query.js

@@ -51,9 +51,7 @@ angular.module('openproject.models')
       return angular.extend.apply(this, [
         {
           'f[]': this.getFilterNames(this.getActiveConfiguredFilters()),
-          'c[]': this.columns.map(function(column) {
-            return column.name;
-           }),
+          'c[]': this.getParamColumns(),
           'group_by': this.groupBy,
           'sort': this.sortation.encode()
         }].concat(this.getActiveConfiguredFilters().map(function(filter) {
@@ -141,6 +139,17 @@ angular.module('openproject.models')
       });
     },
 
+    getParamColumns: function(){
+      var selectedColumns = this.columns.map(function(column) {
+        return column.name;
+      });
+      // To be able to group the work packages we need to add in the group by column if it is not already in the selected columns
+      if(selectedColumns.indexOf(this.groupBy) == -1){
+        selectedColumns.push(this.groupBy);
+      }
+      return selectedColumns;
+    },
+
     getFilterByName: function(filterName) {
       return this.filters.filter(function(filter){
         return filter.name === filterName;

public/templates/work_packages/work_packages_table.html

@@ -61,7 +61,7 @@
         </span>
 
         <span>
-          <span work-package-column work-package="row.object" column="groupByColumn">
+          <span work-package-column work-package="row.object" column="groupByColumn" display-empty="'-'">
           </span>
 
           <span class="count">