diff --git a/app/models/group.rb b/app/models/group.rb
--- a/app/models/group.rb
+++ b/app/models/group.rb
@@ -10,7 +10,7 @@
 
   def add_users_skip_existing(users_list)
     new_list = []
-    users_list.each do |u|
+    users_list.uniq.each do |u|
       new_list << u unless users.include? u
     end
     users << new_list
diff --git a/app/models/user.rb b/app/models/user.rb
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -82,6 +82,10 @@
     end
   end
 
+  def login_with_name
+    "[#{login}] #{full_name}"
+  end
+
   def admin?
     has_role?('admin')
   end
diff --git a/app/views/groups/show.html.haml b/app/views/groups/show.html.haml
--- a/app/views/groups/show.html.haml
+++ b/app/views/groups/show.html.haml
@@ -27,7 +27,7 @@
           =form_tag add_user_group_path(@group), class: 'form-inline' do
             .form-group
               =label_tag :user_id, "User"
-              =select_tag :user_id, options_from_collection_for_select(User.all,'id','full_name'), class: 'select2', style: 'width: 10em';
+              =select_tag :user_id, options_from_collection_for_select(User.all,'id','login_with_name'), class: 'select2', style: 'width: 25em';
             =submit_tag "Add",class: 'btn btn-primary'
 
 
@@ -59,7 +59,7 @@
           =form_tag add_problem_group_path(@group), class: 'form-inline' do
             .form-group
               =label_tag :problem_id, "Problem"
-              =select_tag :problem_id, options_from_collection_for_select(Problem.all,'id','full_name'), class: 'select2', style: 'width: 10em';
+              =select_tag :problem_id, options_from_collection_for_select(Problem.all,'id','long_name'), class: 'select2', style: 'width: 25em';
             =submit_tag "Add",class: 'btn btn-primary'