Index: test/functional/issues_controller_test.rb
===================================================================
--- test/functional/issues_controller_test.rb	(revision 3767)
+++ test/functional/issues_controller_test.rb	(working copy)
@@ -1126,6 +1126,16 @@
     issue = Issue.first(:order => 'id DESC')
     assert_redirected_to :controller => 'issues', :action => 'show', :id => issue
   end
+
+  def test_copy_to_another_project_and_relate
+    @request.session[:user_id] = 2
+    Setting.cross_project_issue_relations = 1
+    post :move, :ids => [1], :new_project_id => 2, :copy_options => {:copy => '1'}, :follow => '1'
+    issue = Issue.first(:order => 'id DESC')
+    orig = Issue.last(:order => 'id DESC')
+    assert_equal issue.subject, orig.subject
+    assert_not_equal 0, issue.relations_from.size
+  end
   
   def test_context_menu_one_issue
     @request.session[:user_id] = 2
Index: app/controllers/issues_controller.rb
===================================================================
--- app/controllers/issues_controller.rb	(revision 3767)
+++ app/controllers/issues_controller.rb	(working copy)
@@ -274,6 +274,13 @@
         call_hook(:controller_issues_move_before_save, { :params => params, :issue => issue, :target_project => @target_project, :copy => !!@copy })
         if r = issue.move_to_project(@target_project, new_tracker, {:copy => @copy, :attributes => changed_attributes})
           moved_issues << r
+          if @copy && Setting.cross_project_issue_relations?
+            relation = IssueRelation.new
+            relation.issue_to = issue
+            relation.issue_from = r
+            relation.relation_type = "duplicates"
+            relation.save
+          end
         else
           unsaved_issue_ids << issue.id
         end