diff --git a/src/main/scala/gitbucket/core/controller/IndexController.scala b/src/main/scala/gitbucket/core/controller/IndexController.scala
index 51d26f6..0d69ebe 100644
--- a/src/main/scala/gitbucket/core/controller/IndexController.scala
+++ b/src/main/scala/gitbucket/core/controller/IndexController.scala
@@ -108,12 +108,18 @@
    */
   get("/_user/proposals")(usersOnly {
     contentType = formats("json")
+    val user  = params("user").toBoolean
+    val group = params("group").toBoolean
     org.json4s.jackson.Serialization.write(
-      Map("options" -> (if(params.get("userOnly").isDefined) {
-        getAllUsers(false).filter(!_.isGroupAccount).map { t => (t.userName, t.isGroupAccount) }.toArray
-      } else {
-        getAllUsers(false).map { t => (t.userName, t.isGroupAccount) }.toArray
-      }).map { case (userName, groupAccount) => userName + ":" + groupAccount })
+      Map("options" -> (
+        getAllUsers(false)
+          .withFilter { t => (user, group) match {
+            case (true, true) => true
+            case (true, false) => !t.isGroupAccount
+            case (false, true) => t.isGroupAccount
+            case (false, false) => false
+          }}.map { t => t.userName }
+      ))
     )
   })
 
diff --git a/src/main/scala/gitbucket/core/controller/RepositorySettingsController.scala b/src/main/scala/gitbucket/core/controller/RepositorySettingsController.scala
index 14d24f9..5a2ca91 100644
--- a/src/main/scala/gitbucket/core/controller/RepositorySettingsController.scala
+++ b/src/main/scala/gitbucket/core/controller/RepositorySettingsController.scala
@@ -42,9 +42,9 @@
     "repositoryName"    -> trim(label("Repository Name"    , text(required, maxlength(40), identifier, renameRepositoryName))),
     "description"       -> trim(label("Description"        , optional(text()))),
     "isPrivate"         -> trim(label("Repository Type"    , boolean())),
-    "issuesOption"      -> trim(label("Issues Option"      , text(required))), // TODO enum check
+    "issuesOption"      -> trim(label("Issues Option"      , text(required, featureOption))),
     "externalIssuesUrl" -> trim(label("External Issues URL", optional(text(maxlength(200))))),
-    "wikiOption"        -> trim(label("Wiki Option"        , text(required))), // TODO enum check
+    "wikiOption"        -> trim(label("Wiki Option"        , text(required, featureOption))),
     "externalWikiUrl"   -> trim(label("External Wiki URL"  , optional(text(maxlength(200))))),
     "allowFork"         -> trim(label("Allow Forking"      , boolean()))
   )(OptionsForm.apply)
@@ -56,12 +56,12 @@
     "defaultBranch"  -> trim(label("Default Branch" , text(required, maxlength(100))))
   )(DefaultBranchForm.apply)
 
-  // for collaborator addition
-  case class CollaboratorForm(userName: String)
-
-  val collaboratorForm = mapping(
-    "userName" -> trim(label("Username", text(required, collaborator)))
-  )(CollaboratorForm.apply)
+//  // for collaborator addition
+//  case class CollaboratorForm(userName: String)
+//
+//  val collaboratorForm = mapping(
+//    "userName" -> trim(label("Username", text(required, collaborator)))
+//  )(CollaboratorForm.apply)
 
   // for web hook url addition
   case class WebHookForm(url: String, events: Set[WebHook.Event], ctype: WebHookContentType, token: Option[String])
@@ -178,7 +178,7 @@
   post("/:owner/:repository/settings/collaborators")(ownerOnly { repository =>
     val collaborators = params("collaborators")
     removeCollaborators(repository.owner, repository.name)
-    collaborators.split(",").map { collaborator =>
+    collaborators.split(",").withFilter(_.nonEmpty).map { collaborator =>
       val userName :: permission :: Nil = collaborator.split(":").toList
       addCollaborator(repository.owner, repository.name, userName, permission)
     }
@@ -384,20 +384,20 @@
     }
   }
 
-  /**
-   * Provides Constraint to validate the collaborator name.
-   */
-  private def collaborator: Constraint = new Constraint(){
-    override def validate(name: String, value: String, messages: Messages): Option[String] =
-      getAccountByUserName(value) match {
-        case None => Some("User does not exist.")
-//        case Some(x) if(x.isGroupAccount)
-//                  => Some("User does not exist.")
-        case Some(x) if(x.userName == params("owner") || getCollaborators(params("owner"), params("repository")).contains(x.userName))
-                  => Some(value + " is repository owner.") // TODO also group members?
-        case _    => None
-      }
-  }
+//  /**
+//   * Provides Constraint to validate the collaborator name.
+//   */
+//  private def collaborator: Constraint = new Constraint(){
+//    override def validate(name: String, value: String, messages: Messages): Option[String] =
+//      getAccountByUserName(value) match {
+//        case None => Some("User does not exist.")
+////        case Some(x) if(x.isGroupAccount)
+////                  => Some("User does not exist.")
+//        case Some(x) if(x.userName == params("owner") || getCollaborators(params("owner"), params("repository")).contains(x.userName))
+//                  => Some(value + " is repository owner.") // TODO also group members?
+//        case _    => None
+//      }
+//  }
 
   /**
    * Duplicate check for the rename repository name.
@@ -412,6 +412,15 @@
   }
 
   /**
+   *
+   */
+  private def featureOption: Constraint = new Constraint(){
+    override def validate(name: String, value: String, params: Map[String, String], messages: Messages): Option[String] =
+      if(Seq("DISABLE", "PRIVATE", "PUBLIC").contains(value)) None else Some("Option is invalid.")
+  }
+
+
+  /**
    * Provides Constraint to validate the repository transfer user.
    */
   private def transferUser: Constraint = new Constraint(){
diff --git a/src/main/twirl/gitbucket/core/account/group.scala.html b/src/main/twirl/gitbucket/core/account/group.scala.html
index cb219da..797c669 100644
--- a/src/main/twirl/gitbucket/core/account/group.scala.html
+++ b/src/main/twirl/gitbucket/core/account/group.scala.html
@@ -31,7 +31,7 @@
             <label class="strong">Members</label>
             <ul id="member-list" class="collaborator">
             </ul>
-            @gitbucket.core.helper.html.account("memberName", 200)
+            @gitbucket.core.helper.html.account("memberName", 200, true, false)
             <input type="button" class="btn btn-default" value="Add" id="addMember"/>
             <input type="hidden" id="members" name="members" value="@members.map(member => member.userName + ":" + member.isManager).mkString(",")"/>
             <div>
diff --git a/src/main/twirl/gitbucket/core/admin/usergroup.scala.html b/src/main/twirl/gitbucket/core/admin/usergroup.scala.html
index 1677005..b72ae1d 100644
--- a/src/main/twirl/gitbucket/core/admin/usergroup.scala.html
+++ b/src/main/twirl/gitbucket/core/admin/usergroup.scala.html
@@ -34,7 +34,7 @@
             <label class="strong">Members</label>
             <ul id="member-list" class="collaborator">
             </ul>
-            @gitbucket.core.helper.html.account("memberName", 200)
+            @gitbucket.core.helper.html.account("memberName", 200, true, false)
             <input type="button" class="btn btn-default" value="Add" id="addMember"/>
             <input type="hidden" id="members" name="members" value="@members.map(member => member.userName + ":" + member.isManager).mkString(",")"/>
             <div>
diff --git a/src/main/twirl/gitbucket/core/helper/account.scala.html b/src/main/twirl/gitbucket/core/helper/account.scala.html
index 06964dc..0e14ced 100644
--- a/src/main/twirl/gitbucket/core/helper/account.scala.html
+++ b/src/main/twirl/gitbucket/core/helper/account.scala.html
@@ -1,19 +1,19 @@
-@(id: String, width: Int, userOnly: Boolean = true)(implicit context: gitbucket.core.controller.Context)
+@(id: String, width: Int, user: Boolean, group: Boolean)(implicit context: gitbucket.core.controller.Context)
 <span style="margin-right: 0px;">
   <input type="text" name="@id" id="@id" class="form-control" autocomplete="off" style="width: @{width}px; margin-bottom: 0px; display: inline; vertical-align: middle;"/>
 </span>
 <script>
 $(function(){
   $('#@id').typeahead({
-    highlighter: function(item) {
-      var x = item.split(':');
-      return $('<div><strong>' + x[0] + '</strong>' + (x[1] == 'true' ? ' (group)' : '') + '</div>');
-    },
-    updater: function (item) {
-      return item.split(':')[0];
-    },
+//    highlighter: function(item) {
+//      var x = item.split(':');
+//      return $('<div><strong>' + x[0] + '</strong>' + (x[1] == 'true' ? ' (group)' : '') + '</div>');
+//    },
+//    updater: function (item) {
+//      return item.split(':')[0];
+//    },
     source: function (query, process) {
-      return $.get('@context.path/_user/proposals@if(userOnly){?userOnly}', { query: query },
+      return $.get('@context.path/_user/proposals', { query: query, user: @user, group: @group },
         function (data) {
           return process(data.options);
         });
diff --git a/src/main/twirl/gitbucket/core/settings/collaborators.scala.html b/src/main/twirl/gitbucket/core/settings/collaborators.scala.html
index f0cf1ec..3aeb44d 100644
--- a/src/main/twirl/gitbucket/core/settings/collaborators.scala.html
+++ b/src/main/twirl/gitbucket/core/settings/collaborators.scala.html
@@ -6,17 +6,35 @@
 @gitbucket.core.html.main("Settings", Some(repository)){
   @gitbucket.core.html.menu("settings", repository){
     @gitbucket.core.settings.html.menu("collaborators", repository){
-      <h3>Manage Collaborators</h3>
       <form id="form" method="post" action="@helpers.url(repository)/settings/collaborators">
-        <ul id="collaborator-list" class="collaborator">
-        </ul>
-        @gitbucket.core.helper.html.account("userName", 200, false)
-        <input type="button" class="btn btn-default" value="Add" id="addCollaborator"/>
-        <input type="hidden" id="collaborators" name="collaborators" value="@collaborators.map(x => x._1.userName + ":" + x._1.permission).mkString(",")"/>
-        <div>
-          <span class="error" id="error-collaborators"></span>
+        <div class="panel panel-default">
+          <div class="panel-heading strong">Collaborators</div>
+          <div class="panel-body">
+            <ul id="collaborator-list" class="collaborator">
+            </ul>
+            @gitbucket.core.helper.html.account("userName-collaborator", 200, true, false)
+            <input type="button" class="btn btn-default add" value="Add" id="addCollaborator"/>
+            <div>
+              <span class="error" id="error-collaborator"></span>
+            </div>
+          </div>
         </div>
+
+        <div class="panel panel-default">
+          <div class="panel-heading strong">Groups</div>
+          <div class="panel-body">
+            <ul id="group-list" class="collaborator">
+            </ul>
+            @gitbucket.core.helper.html.account("userName-group", 200, false, true)
+            <input type="button" class="btn btn-default add" value="Add" id="addGroup"/>
+            <div>
+              <span class="error" id="error-group"></span>
+            </div>
+          </div>
+        </div>
+
         <div class="align-right" style="margin-top: 20px;">
+          <input type="hidden" id="collaborators" name="collaborators" />
           <input type="submit" class="btn btn-success" value="Apply changes"/>
         </div>
       </form>
@@ -26,24 +44,32 @@
 <script>
 $(function(){
   $('input[type=submit]').click(function(){
-    updateCollaborators();
+    updateValues();
   });
 
-  $('#addCollaborator').click(function(){
-    $('#error-collaborators').text('');
-    var userName = $('#userName').val();
+  $('.add').click(function(){
+    var id = $(this).attr('id') == 'addCollaborator' ? 'collaborator' : 'group';
+
+    $('#error-' + id).text('');
+    var userName = $('#userName-' + id).val();
 
     // check empty
     if($.trim(userName) == ''){
       return false;
     }
 
+    // check owner
+    var owner = '@repository.owner' == userName
+    if(owner){
+      $('#error-' + id).text('User is owner of this repository.');
+      return false;
+    }
     // check duplication
-    var exists = $('#collaborator-list li').filter(function(){
+    var exists = $('#' + id + '-list li').filter(function(){
       return $(this).data('name') == userName;
     }).length > 0;
     if(exists){
-      $('#error-collaborators').text('User has been already added.');
+      $('#error-' + id).text('User has been already added.');
       return false;
     }
 
@@ -51,9 +77,9 @@
     $.post('@context.path/_user/existence', { 'userName': userName },
       function(data, status){
         if(data != ''){
-          addCollaboratorHTML(userName, '@Permission.ADMIN.name', data == 'group');
+          addListHTML(userName, '@Permission.ADMIN.name', '#' + id + '-list');
         } else {
-          $('#error-collaborators').text('User does not exist.');
+          $('#error-' + id).text('User does not exist.');
         }
       });
   });
@@ -63,15 +89,15 @@
   });
 
   // Don't submit form by ENTER key
-  $('#userName').keypress(function(e){
+  $('#userName-collaborator, #userName-group').keypress(function(e){
     return !(e.keyCode == 13);
   });
 
   @collaborators.map { case (collaborator, isGroup) =>
-    addCollaboratorHTML('@collaborator.collaboratorName', '@collaborator.permission', @isGroup);
+    addListHTML('@collaborator.collaboratorName', '@collaborator.permission', @if(isGroup){'#group-list'}else{'#collaborator-list'});
   }
 
-  function addCollaboratorHTML(userName, permission, isGroup){
+  function addListHTML(userName, permission, id){
     var adminButton = $('<label class="btn btn-default btn-mini"><input type="radio" value="@Permission.ADMIN.name" name="' + userName + '">Admin</label>');
     if(permission == '@Permission.ADMIN.name'){
       adminButton.addClass('active');
@@ -85,24 +111,29 @@
       readButton.addClass('active');
     }
 
-    $('#collaborator-list').append($('<li>')
+    $(id).append($('<li>')
       .data('name', userName)
       .append($('<div class="btn-group permission" data-toggle="buttons">')
         .append(adminButton)
         .append(writeButton)
         .append(readButton))
       .append(' ')
-      .append($('<a>').attr('href', '@context.path/' + userName).text(userName))
-      .append(isGroup ? ' (group)' : '')
+      .append($('<a target="_blank">').attr('href', '@context.path/' + userName).text(userName))
       .append($('<a href="#" class="remove pull-right">(remove)</a>')));
   }
 
-  function updateCollaborators(){
+  function updateValues(){
     var collaborators = $('#collaborator-list li').map(function(i, e){
       var userName = $(e).data('name');
       return userName + ':' + $(e).find('label.active input[type=radio]').attr('value');
     }).get().join(',');
-    $('#collaborators').val(collaborators);
+
+    var groups = $('#group-list li').map(function(i, e){
+      var userName = $(e).data('name');
+      return userName + ':' + $(e).find('label.active input[type=radio]').attr('value');
+    }).get().join(',');
+
+    $('#collaborators').val(collaborators + ',' + groups);
   }
 });
 </script>
\ No newline at end of file
diff --git a/src/main/twirl/gitbucket/core/settings/danger.scala.html b/src/main/twirl/gitbucket/core/settings/danger.scala.html
index 60b4007..7df1170 100644
--- a/src/main/twirl/gitbucket/core/settings/danger.scala.html
+++ b/src/main/twirl/gitbucket/core/settings/danger.scala.html
@@ -13,7 +13,7 @@
               <div>
                 Transfer this repo to another user or to group.
                 <div class="pull-right">
-                  @gitbucket.core.helper.html.account("newOwner", 200)
+                  @gitbucket.core.helper.html.account("newOwner", 200, true, true)
                   <input type="submit" class="btn btn-danger" value="Transfer"/>
                   <div>
                     <span id="error-newOwner" class="error"></span>