diff --git a/app/controllers/graders_controller.rb b/app/controllers/graders_controller.rb
--- a/app/controllers/graders_controller.rb
+++ b/app/controllers/graders_controller.rb
@@ -1,22 +1,6 @@
 class GradersController < ApplicationController
 
-  before_filter :admin_authorization, except: [ :submission ]
-  before_filter(only: [:submission]) {
-    #check if authenticated
-    return false unless authenticate
-
-    #admin always has privileged
-    if @current_user.admin?
-      return true
-    end
-
-    if GraderConfiguration["right.user_view_submission"] and Submission.find(params[:id]).problem.available?
-      return true
-    else
-      unauthorized_redirect
-      return false
-    end
-  }
+  before_filter :admin_authorization
 
   verify :method => :post, :only => ['clear_all', 
                                      'start_exam',
@@ -77,25 +61,6 @@
     @task = Task.find(params[:id])
   end
 
-  def submission
-    @submission = Submission.find(params[:id])
-    formatter = Rouge::Formatters::HTML.new(css_class: 'highlight', line_numbers: true )
-    lexer = case @submission.language.name
-      when "c"      then Rouge::Lexers::C.new
-      when "cpp"    then Rouge::Lexers::Cpp.new
-      when "pas"    then Rouge::Lexers::Pas.new
-      when "ruby"   then Rouge::Lexers::Ruby.new
-      when "python" then Rouge::Lexers::Python.new
-      when "java"   then Rouge::Lexers::Java.new
-      when "php"    then Rouge::Lexers::PHP.new
-    end
-    @formatted_code = formatter.format(lexer.lex(@submission.source))
-    @css_style = Rouge::Themes::ThankfulEyes.render(scope: '.highlight')
-
-    user = User.find(session[:user_id])
-    SubmissionViewLog.create(user_id: session[:user_id],submission_id: @submission.id) unless user.admin?
-
-  end
 
   # various grader controls
 
diff --git a/app/controllers/groups_controller.rb b/app/controllers/groups_controller.rb
--- a/app/controllers/groups_controller.rb
+++ b/app/controllers/groups_controller.rb
@@ -1,7 +1,7 @@
 class GroupsController < ApplicationController
   before_action :set_group, only: [:show, :edit, :update, :destroy,
-                                   :add_user, :remove_user,
-                                   :add_problem, :remove_problem,
+                                   :add_user, :remove_user,:remove_all_user,
+                                   :add_problem, :remove_problem,:remove_all_problem,
                                   ]
   before_action :authenticate, :admin_authorization
 
@@ -55,6 +55,16 @@
     redirect_to group_path(@group), flash: {success: "User #{user.login} was removed from the group #{@group.name}"}
   end
 
+  def remove_all_user
+    @group.users.clear
+    redirect_to group_path(@group), alert: 'All users removed'
+  end
+
+  def remove_all_problem
+    @group.problems.clear
+    redirect_to group_path(@group), alert: 'All problems removed'
+  end
+
   def add_user
     user = User.find(params[:user_id])
     begin
diff --git a/app/controllers/tasks_controller.rb b/app/controllers/tasks_controller.rb
--- a/app/controllers/tasks_controller.rb
+++ b/app/controllers/tasks_controller.rb
@@ -26,7 +26,7 @@
   # this has problem-level access control
   def download
     problem = Problem.find(params[:id])
-    if !problem or !problem.available or !@user.can_view_problem? problem
+    unless @current_user.can_view_problem? problem
       redirect_to :action => 'index' and return
     end
 
diff --git a/app/models/user.rb b/app/models/user.rb
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -339,11 +339,8 @@
   end
 
   def can_view_problem?(problem)
-    if not GraderConfiguration.multicontests?
-      return problem.available
-    else
-      return problem_in_user_contests? problem
-    end
+    return true if admin?
+    return available_problems.include? problem
   end
 
   def self.clear_last_login
diff --git a/app/views/graders/submission.html.haml b/app/views/graders/submission.html.haml
deleted file mode 100644
--- a/app/views/graders/submission.html.haml
+++ /dev/null
@@ -1,87 +0,0 @@
-%h1= "Submission: #{@submission.id}"
-
-%textarea#data{style: "display:none;"}
-  :preserve
-    #{@submission.source}
-
-//%div.highlight{:style => "border: 1px solid black;"}
-//=@formatted_code.html_safe
-.containter
-  .row
-    .col-md-7
-      %h2 Source Code
-    .col-md-5
-      %h2 Stat
-  .row
-    .col-md-7
-      %div#editor{ style: "font-size: 14px; height: 400px; border-radius:5px;" }
-      :javascript
-        e = ace.edit("editor")
-        e.setOptions({ maxLines: Infinity })
-        e.setValue($("#data").text())
-        e.gotoLine(1)
-        e.getSession().setMode("#{get_ace_mode(@submission.language)}")
-        e.setReadOnly(true)
-    .col-md-5
-      %table.table.table-striped
-        %tr
-          %td.text-right
-            %strong User
-          %td
-            - if @submission.user 
-              = link_to "(#{@submission.user.login})", controller: "users", action: "profile", id: @submission.user
-              = @submission.user.full_name
-            - else
-              = "(n/a)"
-        %tr
-          %td.text-right
-            %strong Task
-          %td
-            - if @submission.problem!=nil
-              = link_to "(#{@submission.problem.name})", controller: "problems", action: "stat", id: @submission.problem
-              = @submission.problem.full_name
-            - else
-              = "(n/a)"
-        %tr
-          %td.text-right
-            %strong Tries
-          %td= @submission.number
-        %tr
-          %td.text-right
-            %strong Language
-          %td= @submission.language.pretty_name
-        %tr
-          %td.text-right
-            %strong Submitted
-          %td #{time_ago_in_words(@submission.submitted_at)} ago (at #{@submission.submitted_at.to_formatted_s(:long)})
-        %tr
-          %td.text-right
-            %strong Graded
-          - if @submission.graded_at
-            %td #{time_ago_in_words(@submission.graded_at)} ago (at #{@submission.graded_at.to_formatted_s(:long)})
-          - else
-            %td -
-        %tr
-          %td.text-right
-            %strong Points
-          %td #{@submission.points}/#{@submission.problem.full_score}
-        %tr
-          %td.text-right
-            %strong Comment
-          %td #{@submission.grader_comment}
-        %tr
-          %td.text-right
-            %strong Runtime (s)
-          %td #{@submission.max_runtime}
-        %tr
-          %td.text-right
-            %strong Memory (kb)
-          %td #{@submission.peak_memory}
-        - if session[:admin]
-          %tr
-            %td.text-right
-              %strong IP
-            %td #{@submission.ip_address}
-
-
-
diff --git a/app/views/graders/task.html.haml b/app/views/graders/task.html.haml
--- a/app/views/graders/task.html.haml
+++ b/app/views/graders/task.html.haml
@@ -9,7 +9,7 @@
   %br/
   = "Submission: #{@task.submission_id}"
   - if @task.submission !=nil
-    = link_to '[view submission]', :action => 'submission', :id => @task.submission.id
+    = link_to '[view submission]', submission_path( @task.submission.id )
   %br/
   = "Submitted at: #{format_short_time(@task.created_at)}"
   %br/
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
@@ -11,7 +11,8 @@
 = link_to 'Back', groups_path
 
 .row
-  %h1 Group details
+  .col-md-12
+    %h1 Group details
 .row
   .col-md-6
     .panel.panel-default
@@ -31,7 +32,7 @@
               %th Login
               %th Full name
               %th Remark
-              %th
+              %th= link_to 'Remove All', remove_all_user_group_path(@group), method: :delete, :data => { :confirm => "Remove ALL USERS from group?" }, class: 'btn btn-danger btn-sm'
 
           %tbody
             - @group.users.each do |user|
@@ -39,7 +40,7 @@
                 %td= user.login
                 %td= user.full_name
                 %td= user.remark
-                %td= link_to 'Remove', remove_user_group_path(@group,user), :method => :delete, :data => { :confirm => "Remove #{user.full_name}?" }, class: 'btn btn-danger'
+                %td= link_to 'Remove', remove_user_group_path(@group,user), :method => :delete, :data => { :confirm => "Remove #{user.full_name}?" }, class: 'btn btn-danger btn-sm'
   .col-md-6
     .panel.panel-default
       .panel-heading
@@ -59,7 +60,7 @@
               %th name
               %th Full name
               %th Full score
-              %th
+              %th= link_to 'Remove All', remove_all_problem_group_path(@group), method: :delete, :data => { :confirm => "Remove ALL PROBLEMS from group?" }, class: 'btn btn-danger btn-sm'
 
           %tbody
             - @group.problems.each do |problem|
@@ -67,6 +68,6 @@
                 %td= problem.name
                 %td= problem.full_name
                 %td= problem.full_score
-                %td= link_to 'Remove', remove_problem_group_path(@group,problem), :method => :delete, :data => { :confirm => "Remove #{problem.full_name}?" }, class: 'btn btn-danger'
+                %td= link_to 'Remove', remove_problem_group_path(@group,problem), :method => :delete, :data => { :confirm => "Remove #{problem.full_name}?" }, class: 'btn btn-danger btn-sm'
 
 
diff --git a/app/views/problems/index.html.haml b/app/views/problems/index.html.haml
--- a/app/views/problems/index.html.haml
+++ b/app/views/problems/index.html.haml
@@ -21,6 +21,9 @@
     %th Name
     %th Full name
     %th.text-right Full score
+    %th 
+      Submit
+      %sup{class: 'text-primary',data: {toggle: 'tooltip'}, title: 'Admin can always submit to any problem' } [?]
     %th Date added
     %th.text-center
       Avail?
@@ -37,8 +40,11 @@
     %tr{:class => "#{(problem.available) ? "success" : "danger"}", :id => "prob-#{problem.id}", :name => "prob-#{problem.id}"}
       - @problem=problem
       %td= problem.name #in_place_editor_field :problem, :name, {}, :rows=>1
-      %td= problem.full_name #in_place_editor_field :problem, :full_name, {}, :rows=>1
+      %td
+        = problem.full_name #in_place_editor_field :problem, :full_name, {}, :rows=>1
+        = link_to_description_if_any "[#{t 'main.problem_desc'}] <span class='glyphicon glyphicon-file'></span>".html_safe, problem
       %td.text-right= problem.full_score #in_place_editor_field :problem, :full_score, {}, :rows=>1
+      %td= link_to "Submit", direct_edit_problem_submissions_path(problem), class: 'btn btn-xs btn-primary'
       %td= problem.date_added
       %td= toggle_button(@problem.available?, toggle_problem_path(@problem), "problem-avail-#{@problem.id}")
       %td= toggle_button(@problem.view_testcase?, toggle_view_testcase_problem_path(@problem), "problem-view-testcase-#{@problem.id}")
diff --git a/config/routes.rb b/config/routes.rb
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -35,8 +35,13 @@
     member do
       post 'add_user', to: 'groups#add_user', as: 'add_user'
       delete 'remove_user/:user_id', to: 'groups#remove_user', as: 'remove_user'
+      delete 'remove_all_user', to: 'groups#remove_all_user', as: 'remove_all_user'
       post 'add_problem', to: 'groups#add_problem', as: 'add_problem'
       delete 'remove_problem/:problem_id', to: 'groups#remove_problem', as: 'remove_problem'
+      delete 'remove_all_problem', to: 'groups#remove_all_problem', as: 'remove_all_problem'
+    end
+    collection do
+
     end
   end