Same Date not occurs Events

I want that no two or more events will occurs on same dates ,but when i am using this functionality i face javascript errors ,and drag features come ,previous events not shown ,What will be problem while i am using v2.3 Please provide me soulution ,
Thanks in advances


Please check Collisions extension page.
If something is failing for you try replacing collision source file with the version available on the Known issues page.

Best regards,