Index: app/helpers/issues_helper.rb
===================================================================
--- app/helpers/issues_helper.rb	(revision 16545)
+++ app/helpers/issues_helper.rb	(working copy)
@@ -188,6 +188,11 @@
   end
 
   def trackers_options_for_select(issue)
+    trackers = trackers_for_select(issue)
+    trackers.collect {|t| [t.name, t.id]}
+  end
+
+  def trackers_for_select(issue)
     trackers = issue.allowed_target_trackers
     if issue.new_record? && issue.parent_issue_id.present?
       trackers = trackers.reject do |tracker|
@@ -194,7 +199,7 @@
         issue.tracker_id != tracker.id && tracker.disabled_core_fields.include?('parent_issue_id')
       end
     end
-    trackers.collect {|t| [t.name, t.id]}
+    trackers
   end
 
   class IssueFieldsRows
Index: app/models/tracker.rb
===================================================================
--- app/models/tracker.rb	(revision 16545)
+++ app/models/tracker.rb	(working copy)
@@ -76,7 +76,8 @@
     'core_fields',
     'position',
     'custom_field_ids',
-    'project_ids'
+    'project_ids',
+    'description'
 
   def to_s; name end
 
Index: app/views/issues/_form.html.erb
===================================================================
--- app/views/issues/_form.html.erb	(revision 16545)
+++ app/views/issues/_form.html.erb	(working copy)
@@ -15,10 +15,16 @@
 <% end %>
 
 <% if @issue.safe_attribute? 'tracker_id' %>
-<p><%= f.select :tracker_id, trackers_options_for_select(@issue), {:required => true},
-                :onchange => "updateIssueFrom('#{escape_javascript update_issue_form_path(@project, @issue)}', this)" %></p>
+<p>
+  <%= f.select :tracker_id, trackers_options_for_select(@issue), {:required => true},
+                :onchange => "updateIssueFrom('#{escape_javascript update_issue_form_path(@project, @issue)}', this)" %>
+    <a class="icon icon-help" href="#" id="display_tracker_description">
+      <%=h l(:label_description_for_trackers, default: 'Descriptions for trackers') %>
+    </a>
+</p>
 <% end %>
 
+<%= render partial: 'issues/tracker_description', locals: { trackers: trackers_for_select(@issue) } %>
 <% if @issue.safe_attribute? 'subject' %>
 <p><%= f.text_field :subject, :size => 80, :maxlength => 255, :required => true %></p>
 <% end %>
Index: app/views/issues/_tracker_description.html.erb
===================================================================
--- app/views/issues/_tracker_description.html.erb	(nonexistent)
+++ app/views/issues/_tracker_description.html.erb	(working copy)
@@ -0,0 +1,52 @@
+<!-- dialog box -->
+<div id="trackers_description_dialog" style="overflow:visible; display: none;">
+  <h3 class="title"><%= l(:label_description_for_trackers, default: 'Descriptions for trackers') %></h3>
+  <table class="list trackers odd-even">
+    <thead>
+    <th><%= l(:field_description) %></th>
+    <th><%= l(:button_apply) %></th>
+    </thead>
+    <tbody>
+    <% trackers.each do |tracker| %>
+        <tr class="<%= cycle("odd", "even") %>" name="<%= tracker['id'] %>">
+          <td class="description">
+            <h4><%= tracker['name'] %></h4>
+            <%= textilizable(tracker['description']) %>
+          </td>
+          <td>
+            <a href="#" class="icon icon-test" title="<%= l(:button_apply) %>"
+               onclick="applyTracker(<%= tracker['id'] %>, false); return false;"></a>
+          </td>
+        </tr>
+    <% end %>
+    </tbody>
+  </table>
+</div>
+<!-- dialog box -->
+
+<script type="text/javascript">
+    //<![CDATA[
+    $(document).ready(function () {
+        $("#display_tracker_description").click(function (e) {
+            e.preventDefault();
+            showModal('trackers_description_dialog', '500px');
+            var selected_tracker_id = $('#issue_tracker_id').val();
+            updateSelect(selected_tracker_id);
+        });
+    });
+
+    function applyTracker(id) {
+        var target = $('#issue_tracker_id');
+        target.attr("selected", false);
+        target.find('option[value="' + id + '"]').prop('selected', true);
+        target.trigger('change');
+        updateSelect(id);
+    }
+
+    function updateSelect(id) {
+        var target = $("tr[name='" + id + "'] td h4");
+        $('td h4').not(target).removeClass('selected');
+        $(target).addClass('selected');
+    }
+</script>
+
Index: app/views/projects/_form.html.erb
===================================================================
--- app/views/projects/_form.html.erb	(revision 16545)
+++ app/views/projects/_form.html.erb	(working copy)
@@ -53,8 +53,14 @@
 <fieldset class="box tabular" id="project_trackers"><legend><%=l(:label_tracker_plural)%></legend>
 <% @trackers.each do |tracker| %>
     <label class="floating">
-    <%= check_box_tag 'project[tracker_ids][]', tracker.id, @project.trackers.to_a.include?(tracker), :id => nil %>
-    <%= tracker %>
+      <div class="tooltip_wrapper">
+        <%= check_box_tag 'project[tracker_ids][]', tracker.id, @project.trackers.to_a.include?(tracker), :id => nil %>
+        <%= tracker %>
+        <div class="tooltip_body">
+          <p class="tooltip_title"><%= tracker.name %></p>
+          <%= tracker.description %>
+        </div>
+      </div>
     </label>
 <% end %>
 <%= hidden_field_tag 'project[tracker_ids][]', '' %>
Index: app/views/projects/show.html.erb
===================================================================
--- app/views/projects/show.html.erb	(revision 16545)
+++ app/views/projects/show.html.erb	(working copy)
@@ -51,7 +51,13 @@
       <% @trackers.each do |tracker| %>
         <tr>
           <td class="name">
-            <%= link_to tracker.name, project_issues_path(@project, :set_filter => 1, :tracker_id => tracker.id) %>
+            <div class="tooltip_wrapper">
+              <%= link_to tracker.name, project_issues_path(@project, :set_filter => 1, :tracker_id => tracker.id ) %>
+              <div class="tooltip_body">
+                <p class="tooltip_title"><%= tracker.name %></p>
+                <%= tracker.description %>
+              </div>
+            </div>
           </td>
           <td>
             <%= link_to @open_issues_by_tracker[tracker].to_i, project_issues_path(@project, :set_filter => 1, :tracker_id => tracker.id) %>
Index: app/views/trackers/_form.html.erb
===================================================================
--- app/views/trackers/_form.html.erb	(revision 16545)
+++ app/views/trackers/_form.html.erb	(working copy)
@@ -10,6 +10,7 @@
         :required => true %>
 </p>
 <p><%= f.check_box :is_in_roadmap %></p>
+<p><%= f.text_area :description, :rows => 4 %></p>
 <p>
   <label><%= l(:field_core_fields) %></label>
   <% Tracker::CORE_FIELDS.each do |field| %>
Index: app/views/trackers/index.api.rsb
===================================================================
--- app/views/trackers/index.api.rsb	(revision 16545)
+++ app/views/trackers/index.api.rsb	(working copy)
@@ -4,6 +4,7 @@
       api.id tracker.id
       api.name tracker.name
       api.default_status(:id => tracker.default_status.id, :name => tracker.default_status.name) unless tracker.default_status.nil?
+      api.description tracker.description
     end
   end
 end
Index: app/views/trackers/index.html.erb
===================================================================
--- app/views/trackers/index.html.erb	(revision 16545)
+++ app/views/trackers/index.html.erb	(working copy)
@@ -14,7 +14,15 @@
   <tbody>
 <% for tracker in @trackers %>
   <tr>
-  <td class="name"><%= link_to tracker.name, edit_tracker_path(tracker) %></td>
+  <td class="name">
+    <div class="tooltip_wrapper">
+      <%= link_to tracker.name, edit_tracker_path(tracker) %>
+      <div class="tooltip_body">
+        <p class="tooltip_title"><%= tracker.name %></p>
+        <%= tracker.description %>
+      </div>
+    </div>
+  </td>
   <td>
     <% unless tracker.workflow_rules.exists? %>
       <span class="icon icon-warning">
Index: db/migrate/20170503103500_add_trackers_description.rb
===================================================================
--- db/migrate/20170503103500_add_trackers_description.rb	(nonexistent)
+++ db/migrate/20170503103500_add_trackers_description.rb	(working copy)
@@ -0,0 +1,9 @@
+class AddTrackersDescription < ActiveRecord::Migration
+  def self.up
+    add_column :trackers, :description, :string
+  end
+
+  def self.down
+    remove_column :trackers, :description
+  end
+end
Index: public/stylesheets/application.css
===================================================================
--- public/stylesheets/application.css	(revision 16545)
+++ public/stylesheets/application.css	(working copy)
@@ -1462,3 +1462,60 @@
   height:1px;
   overflow:hidden;
 }
+
+/*--- Tooltip: Use to display template description -----*/
+.tooltip_wrapper {
+  color: #555;
+  display: inline-block;
+}
+
+/* Hide tooltip body */
+.tooltip_wrapper .tooltip_body {
+  display: none;
+}
+
+.tooltip_body .tooltip_title {
+  color: #979797;
+  font-weight: bold;
+  font-style: italic;
+  border-bottom: 1px solid #e4e4e4;
+  padding: 3px 0 3px 0;
+  margin-bottom: 4px;
+}
+
+/* Mouse over action */
+.tooltip_wrapper:hover {
+  position: relative;
+  color: #333;
+}
+
+/* tooltip body */
+.tooltip_wrapper:hover .tooltip_body {
+  text-align: left;
+  display: block;
+  position: absolute;
+  left: 60px;
+  top: 120%;
+  font-size: 90%;
+  background-color: #ffffff;
+  width: 260px;
+  padding: 8px 10px 12px;
+  border: 1px solid #CCCCCC;
+  z-index: 20000;
+}
+
+#trackers_description_dialog h4 {
+  color: #979797;
+  font-weight: bold;
+  border-bottom: solid 1px #c0c0c0;
+}
+
+#trackers_description_dialog h4.selected {
+  color: inherit;
+  font-style: italic;
+}
+
+#trackers_description_dialog td {
+  padding: 8px 8px; 8px 4px;
+}
+