diff --git a/app/helpers/settings_helper.rb b/app/helpers/settings_helper.rb
index fcf8ec2e37f9a5315f3f70f39a1d9ce2fdef00ea..0dcdbb040feb1cef161335ce5d317d427299bb2f 100644
--- a/app/helpers/settings_helper.rb
+++ b/app/helpers/settings_helper.rb
@@ -79,7 +79,12 @@ module SettingsHelper
 
   def setting_label(setting, options={})
     label = options.delete(:label)
-    label != false ? label_tag("settings_#{setting}", l(label || "setting_#{setting}"), options[:label_options]).html_safe : ''
+    if label == false
+      ''
+    else
+      text = label.is_a?(String) ? label : l(label || "setting_#{setting}")
+      label_tag("settings_#{setting}", text, options[:label_options])
+    end
   end
 
   # Renders a notification field for a Redmine::Notifiable option
@@ -123,6 +128,24 @@ module SettingsHelper
       [:label_cross_project_descendants, 'descendants']
     ]
 
+    options.map {|label, value| [l(label), value.to_s]}
+  end
+
+  def parent_issue_dates_options
+    options = [
+      [:label_parent_task_attributes_derived, 'derived'],
+      [:label_parent_task_attributes_independent, 'independent']
+    ]
+
+    options.map {|label, value| [l(label), value.to_s]}
+  end
+
+  def parent_issue_priority_options
+    options = [
+      [:label_parent_task_attributes_derived, 'derived'],
+      [:label_parent_task_attributes_independent, 'independent']
+    ]
+
     options.map {|label, value| [l(label), value.to_s]}
   end
 
diff --git a/app/models/issue.rb b/app/models/issue.rb
index 9ea7f6c578e3fe804fa4243cb0318bd246c34628..7d04d1e15236deda0b0072b1f8c2c98f17058d69 100644
--- a/app/models/issue.rb
+++ b/app/models/issue.rb
@@ -426,6 +426,15 @@ class Issue < ActiveRecord::Base
      	# Make sure that project_id can always be set for new issues
       names |= %w(project_id)
     end
+    if dates_derived?
+      names -= %w(start_date due_date)
+    end
+    if priority_derived?
+      names -= %w(priority_id)
+    end
+    unless leaf?
+      names -= %w(done_ratio estimated_hours)
+    end
     names
   end
 
@@ -463,10 +472,6 @@ class Issue < ActiveRecord::Base
     attrs = delete_unsafe_attributes(attrs, user)
     return if attrs.empty?
 
-    unless leaf?
-      attrs.reject! {|k,v| %w(priority_id done_ratio start_date due_date estimated_hours).include?(k)}
-    end
-
     if attrs['parent_issue_id'].present?
       s = attrs['parent_issue_id'].to_s
       unless (m = s.match(%r{\A#?(\d+)\z})) && (m[1] == parent_id.to_s || Issue.visible(user).exists?(m[1]))
@@ -1094,11 +1099,15 @@ class Issue < ActiveRecord::Base
   end
 
   def soonest_start(reload=false)
-    @soonest_start = nil if reload
-    @soonest_start ||= (
-        relations_to(reload).collect{|relation| relation.successor_soonest_start} +
-        [(@parent_issue || parent).try(:soonest_start)]
-      ).compact.max
+    if @soonest_start.nil? || reload
+      dates = relations_to(reload).collect{|relation| relation.successor_soonest_start}
+      p = @parent_issue || parent
+      if p && Setting.parent_issue_dates == 'derived'
+        dates << p.soonest_start
+      end
+      @soonest_start = dates.compact.max
+    end
+    @soonest_start
   end
 
   # Sets start_date on the given date or the next working day
@@ -1114,7 +1123,7 @@ class Issue < ActiveRecord::Base
   # If the issue is a parent task, this is done by rescheduling its subtasks.
   def reschedule_on!(date)
     return if date.nil?
-    if leaf?
+    if leaf? || !dates_derived?
       if start_date.nil? || start_date != date
         if start_date && start_date > date
           # Issue can not be moved earlier than its soonest start date
@@ -1144,6 +1153,14 @@ class Issue < ActiveRecord::Base
     end
   end
 
+  def dates_derived?
+    !leaf? && Setting.parent_issue_dates == 'derived'
+  end
+
+  def priority_derived?
+    !leaf? && Setting.parent_issue_priority == 'derived'
+  end
+
   def <=>(issue)
     if issue.nil?
       -1
@@ -1430,16 +1447,20 @@ class Issue < ActiveRecord::Base
 
   def recalculate_attributes_for(issue_id)
     if issue_id && p = Issue.find_by_id(issue_id)
-      # priority = highest priority of children
-      if priority_position = p.children.joins(:priority).maximum("#{IssuePriority.table_name}.position")
-        p.priority = IssuePriority.find_by_position(priority_position)
+      if p.priority_derived?
+        # priority = highest priority of children
+        if priority_position = p.children.joins(:priority).maximum("#{IssuePriority.table_name}.position")
+          p.priority = IssuePriority.find_by_position(priority_position)
+        end
       end
 
-      # start/due dates = lowest/highest dates of children
-      p.start_date = p.children.minimum(:start_date)
-      p.due_date = p.children.maximum(:due_date)
-      if p.start_date && p.due_date && p.due_date < p.start_date
-        p.start_date, p.due_date = p.due_date, p.start_date
+      if p.dates_derived?
+        # start/due dates = lowest/highest dates of children
+        p.start_date = p.children.minimum(:start_date)
+        p.due_date = p.children.maximum(:due_date)
+        if p.start_date && p.due_date && p.due_date < p.start_date
+          p.start_date, p.due_date = p.due_date, p.start_date
+        end
       end
 
       # done ratio = weighted average ratio of leaves
diff --git a/app/views/issues/_attributes.html.erb b/app/views/issues/_attributes.html.erb
index 61ffa8ae3e8ad422cb8ea92073658dfa2ecaeae7..3d5f85c7bd6da873ec9f85641098cd8574934af4 100644
--- a/app/views/issues/_attributes.html.erb
+++ b/app/views/issues/_attributes.html.erb
@@ -48,25 +48,23 @@
 
 <% if @issue.safe_attribute? 'start_date' %>
 <p id="start_date_area">
-  <%= f.text_field(:start_date, :size => 10, :disabled => !@issue.leaf?,
-                   :required => @issue.required_attribute?('start_date')) %>
+  <%= f.text_field(:start_date, :size => 10, :required => @issue.required_attribute?('start_date')) %>
   <%= calendar_for('issue_start_date') if @issue.leaf? %>
 </p>
 <% end %>
 
 <% if @issue.safe_attribute? 'due_date' %>
 <p id="due_date_area">
-  <%= f.text_field(:due_date, :size => 10, :disabled => !@issue.leaf?,
-                   :required => @issue.required_attribute?('due_date')) %>
+  <%= f.text_field(:due_date, :size => 10, :required => @issue.required_attribute?('due_date')) %>
   <%= calendar_for('issue_due_date') if @issue.leaf? %>
 </p>
 <% end %>
 
 <% if @issue.safe_attribute? 'estimated_hours' %>
-<p><%= f.text_field :estimated_hours, :size => 3, :disabled => !@issue.leaf?, :required => @issue.required_attribute?('estimated_hours') %> <%= l(:field_hours) %></p>
+<p><%= f.text_field :estimated_hours, :size => 3, :required => @issue.required_attribute?('estimated_hours') %> <%= l(:field_hours) %></p>
 <% end %>
 
-<% if @issue.safe_attribute?('done_ratio') && @issue.leaf? && Issue.use_field_for_done_ratio? %>
+<% if @issue.safe_attribute?('done_ratio') && Issue.use_field_for_done_ratio? %>
 <p><%= f.select :done_ratio, ((0..10).to_a.collect {|r| ["#{r*10} %", r*10] }), :required => @issue.required_attribute?('done_ratio') %></p>
 <% end %>
 </div>
diff --git a/app/views/settings/_issues.html.erb b/app/views/settings/_issues.html.erb
index c1e802238c4e4d68d7e9c860d9d87a07b6a5f3a5..a0dfd786c2584ac993373baaebae1c10d544e263 100644
--- a/app/views/settings/_issues.html.erb
+++ b/app/views/settings/_issues.html.erb
@@ -22,6 +22,15 @@
 <p><%= setting_text_field :gantt_items_limit, :size => 6 %></p>
 </div>
 
+<fieldset class="box">
+  <legend><%= l(:label_parent_task_attributes) %></legend>
+  <div class="tabular settings">
+    <p><%= setting_select :parent_issue_dates, parent_issue_dates_options, :label => "#{l(:field_start_date)} / #{l(:field_due_date)}" %></p>
+
+    <p><%= setting_select :parent_issue_priority, parent_issue_priority_options, :label => :field_priority %></p>
+  </div>
+</fieldset>
+
 <fieldset class="box">
   <legend><%= l(:setting_issue_list_default_columns) %></legend>
   <%= render_query_columns_selection(
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 1f205b0ff13ecce0a951f38e9147c01f161c70af..92b2ffdebed8681f99befa31c0e85499ef391cf0 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -941,6 +941,9 @@ en:
   label_enable_notifications: Enable notifications
   label_disable_notifications: Disable notifications
   label_blank_value: blank
+  label_parent_task_attributes: Parent tasks attributes
+  label_parent_task_attributes_derived: Calculated from subtasks
+  label_parent_task_attributes_independent: Independent of subtasks
 
   button_login: Login
   button_submit: Submit
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 54dc13a61c877e2979ce16160ef98f5f8ddd8ad4..53937527764980901903605d881c9cc9567404db 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -961,6 +961,7 @@ fr:
   label_enable_notifications: Activer les notifications
   label_disable_notifications: Désactiver les notifications
   label_blank_value: non renseigné
+  label_parent_task_attributes: Attributs des tâches parentes
 
   button_login: Connexion
   button_submit: Soumettre
diff --git a/config/settings.yml b/config/settings.yml
index e5093dd58079b9729089fc7ed1de05cd81cbe7c5..6a163c72fc14ee22e0a8db98d0a6954b166ab0a9 100644
--- a/config/settings.yml
+++ b/config/settings.yml
@@ -146,6 +146,10 @@ cross_project_issue_relations:
 # Enables subtasks to be in other projects
 cross_project_subtasks:
   default: 'tree'
+parent_issue_dates:
+  default: 'derived'
+parent_issue_priority:
+  default: 'derived'
 link_copied_issue:
   default: 'ask'
 issue_group_assignment:
diff --git a/test/object_helpers.rb b/test/object_helpers.rb
index 2b1fa2f61afadc6dc95956f22035562c00d21c22..7061e75c13db64281fc49ce1e8256da58a998890 100644
--- a/test/object_helpers.rb
+++ b/test/object_helpers.rb
@@ -105,6 +105,12 @@ module ObjectHelpers
     issue.reload
   end
 
+  def Issue.generate_with_child!(attributes={})
+    issue = Issue.generate!(attributes)
+    Issue.generate!(:parent_issue_id => issue.id)
+    issue.reload
+  end
+
   def Journal.generate!(attributes={})
     journal = Journal.new(attributes)
     journal.user ||= User.first
diff --git a/test/unit/issue_nested_set_test.rb b/test/unit/issue_nested_set_test.rb
index 6fb5b00451cd101332e495793a8f34598adef36a..632464872ee3a44c815abac6729e37926161ad18 100644
--- a/test/unit/issue_nested_set_test.rb
+++ b/test/unit/issue_nested_set_test.rb
@@ -287,35 +287,6 @@ class IssueNestedSetTest < ActiveSupport::TestCase
     end
   end
 
-  def test_parent_priority_should_be_the_highest_child_priority
-    parent = Issue.generate!(:priority => IssuePriority.find_by_name('Normal'))
-    # Create children
-    child1 = parent.generate_child!(:priority => IssuePriority.find_by_name('High'))
-    assert_equal 'High', parent.reload.priority.name
-    child2 = child1.generate_child!(:priority => IssuePriority.find_by_name('Immediate'))
-    assert_equal 'Immediate', child1.reload.priority.name
-    assert_equal 'Immediate', parent.reload.priority.name
-    child3 = parent.generate_child!(:priority => IssuePriority.find_by_name('Low'))
-    assert_equal 'Immediate', parent.reload.priority.name
-    # Destroy a child
-    child1.destroy
-    assert_equal 'Low', parent.reload.priority.name
-    # Update a child
-    child3.reload.priority = IssuePriority.find_by_name('Normal')
-    child3.save!
-    assert_equal 'Normal', parent.reload.priority.name
-  end
-
-  def test_parent_dates_should_be_lowest_start_and_highest_due_dates
-    parent = Issue.generate!
-    parent.generate_child!(:start_date => '2010-01-25', :due_date => '2010-02-15')
-    parent.generate_child!(                             :due_date => '2010-02-13')
-    parent.generate_child!(:start_date => '2010-02-01', :due_date => '2010-02-22')
-    parent.reload
-    assert_equal Date.parse('2010-01-25'), parent.start_date
-    assert_equal Date.parse('2010-02-22'), parent.due_date
-  end
-
   def test_parent_done_ratio_should_be_average_done_ratio_of_leaves
     parent = Issue.generate!
     parent.generate_child!(:done_ratio => 20)
@@ -390,20 +361,6 @@ class IssueNestedSetTest < ActiveSupport::TestCase
     assert_nil first_parent.reload.estimated_hours
   end
 
-  def test_reschuling_a_parent_should_reschedule_subtasks
-    parent = Issue.generate!
-    c1 = parent.generate_child!(:start_date => '2010-05-12', :due_date => '2010-05-18')
-    c2 = parent.generate_child!(:start_date => '2010-06-03', :due_date => '2010-06-10')
-    parent.reload
-    parent.reschedule_on!(Date.parse('2010-06-02'))
-    c1.reload
-    assert_equal [Date.parse('2010-06-02'), Date.parse('2010-06-08')], [c1.start_date, c1.due_date]
-    c2.reload
-    assert_equal [Date.parse('2010-06-03'), Date.parse('2010-06-10')], [c2.start_date, c2.due_date] # no change
-    parent.reload
-    assert_equal [Date.parse('2010-06-02'), Date.parse('2010-06-10')], [parent.start_date, parent.due_date]
-  end
-
   def test_project_copy_should_copy_issue_tree
     p = Project.create!(:name => 'Tree copy', :identifier => 'tree-copy', :tracker_ids => [1, 2])
     i1 = Issue.generate!(:project => p, :subject => 'i1')
diff --git a/test/unit/issue_subtasking_test.rb b/test/unit/issue_subtasking_test.rb
new file mode 100644
index 0000000000000000000000000000000000000000..621af178a5dfa78a5a022318800f42d8ebba3553
--- /dev/null
+++ b/test/unit/issue_subtasking_test.rb
@@ -0,0 +1,146 @@
+# Redmine - project management software
+# Copyright (C) 2006-2015  Jean-Philippe Lang
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+require File.expand_path('../../test_helper', __FILE__)
+
+class IssueSubtaskingTest < ActiveSupport::TestCase
+  fixtures :projects, :users, :roles, :members, :member_roles,
+           :trackers, :projects_trackers,
+           :issue_statuses, :issue_categories, :enumerations,
+           :issues
+
+  def test_leaf_planning_fields_should_be_editable
+    issue = Issue.generate!
+    user = User.find(1)
+    %w(priority_id done_ratio start_date due_date estimated_hours).each do |attribute|
+      assert issue.safe_attribute?(attribute, user)
+    end
+  end
+
+  def test_parent_dates_should_be_read_only_with_parent_issue_dates_set_to_derived
+    with_settings :parent_issue_dates => 'derived' do
+      issue = Issue.generate_with_child!
+      user = User.find(1)
+      %w(start_date due_date).each do |attribute|
+        assert !issue.safe_attribute?(attribute, user)
+      end
+    end
+  end
+
+  def test_parent_dates_should_be_lowest_start_and_highest_due_dates_with_parent_issue_dates_set_to_derived
+    with_settings :parent_issue_dates => 'derived' do
+      parent = Issue.generate!
+      parent.generate_child!(:start_date => '2010-01-25', :due_date => '2010-02-15')
+      parent.generate_child!(                             :due_date => '2010-02-13')
+      parent.generate_child!(:start_date => '2010-02-01', :due_date => '2010-02-22')
+      parent.reload
+      assert_equal Date.parse('2010-01-25'), parent.start_date
+      assert_equal Date.parse('2010-02-22'), parent.due_date
+    end
+  end
+
+  def test_reschuling_a_parent_should_reschedule_subtasks_with_parent_issue_dates_set_to_derived
+    with_settings :parent_issue_dates => 'derived' do
+      parent = Issue.generate!
+      c1 = parent.generate_child!(:start_date => '2010-05-12', :due_date => '2010-05-18')
+      c2 = parent.generate_child!(:start_date => '2010-06-03', :due_date => '2010-06-10')
+      parent.reload.reschedule_on!(Date.parse('2010-06-02'))
+      c1.reload
+      assert_equal [Date.parse('2010-06-02'), Date.parse('2010-06-08')], [c1.start_date, c1.due_date]
+      c2.reload
+      assert_equal [Date.parse('2010-06-03'), Date.parse('2010-06-10')], [c2.start_date, c2.due_date] # no change
+      parent.reload
+      assert_equal [Date.parse('2010-06-02'), Date.parse('2010-06-10')], [parent.start_date, parent.due_date]
+    end
+  end
+
+  def test_parent_priority_should_be_read_only_with_parent_issue_priority_set_to_derived
+    with_settings :parent_issue_priority => 'derived' do
+      issue = Issue.generate_with_child!
+      user = User.find(1)
+      assert !issue.safe_attribute?('priority_id', user)
+    end
+  end
+
+  def test_parent_priority_should_be_the_highest_child_priority
+    with_settings :parent_issue_priority => 'derived' do
+      parent = Issue.generate!(:priority => IssuePriority.find_by_name('Normal'))
+      # Create children
+      child1 = parent.generate_child!(:priority => IssuePriority.find_by_name('High'))
+      assert_equal 'High', parent.reload.priority.name
+      child2 = child1.generate_child!(:priority => IssuePriority.find_by_name('Immediate'))
+      assert_equal 'Immediate', child1.reload.priority.name
+      assert_equal 'Immediate', parent.reload.priority.name
+      child3 = parent.generate_child!(:priority => IssuePriority.find_by_name('Low'))
+      assert_equal 'Immediate', parent.reload.priority.name
+      # Destroy a child
+      child1.destroy
+      assert_equal 'Low', parent.reload.priority.name
+      # Update a child
+      child3.reload.priority = IssuePriority.find_by_name('Normal')
+      child3.save!
+      assert_equal 'Normal', parent.reload.priority.name
+    end
+  end
+
+  def test_parent_dates_should_be_editable_with_parent_issue_dates_set_to_independent
+    with_settings :parent_issue_dates => 'independent' do
+      issue = Issue.generate_with_child!
+      user = User.find(1)
+      %w(start_date due_date).each do |attribute|
+        assert issue.safe_attribute?(attribute, user)
+      end
+    end
+  end
+
+  def test_parent_dates_should_not_be_updated_with_parent_issue_dates_set_to_independent
+    with_settings :parent_issue_dates => 'independent' do
+      parent = Issue.generate!(:start_date => '2015-07-01', :due_date => '2015-08-01')
+      parent.generate_child!(:start_date => '2015-06-01', :due_date => '2015-09-01')
+      parent.reload
+      assert_equal Date.parse('2015-07-01'), parent.start_date
+      assert_equal Date.parse('2015-08-01'), parent.due_date
+    end
+  end
+
+  def test_reschuling_a_parent_should_not_reschedule_subtasks_with_parent_issue_dates_set_to_independent
+    with_settings :parent_issue_dates => 'independent' do
+      parent = Issue.generate!(:start_date => '2010-05-01', :due_date => '2010-05-20')
+      c1 = parent.generate_child!(:start_date => '2010-05-12', :due_date => '2010-05-18')
+      parent.reload.reschedule_on!(Date.parse('2010-06-01'))
+      assert_equal Date.parse('2010-06-01'), parent.reload.start_date
+      c1.reload
+      assert_equal [Date.parse('2010-05-12'), Date.parse('2010-05-18')], [c1.start_date, c1.due_date]
+    end
+  end
+
+  def test_parent_priority_should_be_editable_with_parent_issue_priority_set_to_independent
+    with_settings :parent_issue_priority => 'independent' do
+      issue = Issue.generate_with_child!
+      user = User.find(1)
+      assert issue.safe_attribute?('priority_id', user)
+    end
+  end
+
+  def test_parent_priority_should_not_be_updated_with_parent_issue_priority_set_to_independent
+    with_settings :parent_issue_priority => 'independent' do
+      parent = Issue.generate!(:priority => IssuePriority.find_by_name('Normal'))
+      child1 = parent.generate_child!(:priority => IssuePriority.find_by_name('High'))
+      assert_equal 'Normal', parent.reload.priority.name
+    end
+  end
+end