When you encounter issues with opening a pop-up window by clicking a button multiple times in MVC4 (or any other version of ASP.NET MVC), it's often related to the handling of the pop-up window or the button click event. Here are some common reasons for this issue and possible solutions:
Multiple Pop-up Windows: If you are opening multiple pop-up windows on each button click without closing the previous ones, you might end up with multiple windows overlapping each other. Make sure to close the existing pop-up window before opening a new one.
Asynchronous Requests: If you are making asynchronous (AJAX) requests on button click, ensure that the requests do not open pop-up windows multiple times when they complete. Handle the response from the AJAX request appropriately to prevent multiple pop-ups from appearing.
Disable Button during Processing: To avoid multiple clicks causing multiple pop-up openings, you can disable the button during the process of opening the pop-up window and enable it once the pop-up is closed.
Debouncing or Throttling: Implement debouncing or throttling techniques to limit the number of clicks that trigger the pop-up opening. This can prevent multiple rapid clicks from causing issues.
Cache Issues: If your pop-up window uses caching, it might display outdated content when opened multiple times. Ensure that the pop-up content is not cached, or handle cache management properly to avoid this issue.
Server-Side Handling: If the pop-up window performs server-side processing, ensure that you handle any concurrency issues or prevent multiple instances of the server-side process from running simultaneously.
Check Dependencies: If you are using any third-party libraries or plugins for the pop-up functionality, ensure that they are functioning correctly and not causing any conflicts.