diff --git a/time/app/models/time_entry.rb b/time/app/models/time_entry.rb
index a8c542a90..513652911 100644
--- a/time/app/models/time_entry.rb
+++ b/time/app/models/time_entry.rb
@@ -17,7 +17,7 @@ class TimeEntry < ActiveRecord::Base
   def validate
     errors.add :hours, :activerecord_error_invalid if hours && hours < 0
     errors.add :project_id, :activerecord_error_invalid if project.nil?
-    errors.add :issue_id, :activerecord_error_invalid if issue && project!=issue.project
+    errors.add :issue_id, :activerecord_error_invalid if (issue_id && !issue) || (issue && project!=issue.project)
   end
   
   def spent_on=(date)