ASP.NET Web Form Page in new window opened via javascript window.open()

I’ve an ASP.NET page already published, and I open it from a third party application widget using a script window.open().

The script is working fine and also the page, but my problem is when I stay for a while not doing anything (for example 5 min) on the opened window the page stopped working, I tried to click a link button in that page but it’s not working. Then I close the window and open it again then everything goes fine.

This problem makes many issues for me because it should affect on the third party system.

I think maybe there is some period of time for that window but I cannot catch the problem.

Is there any solution for this case ?

NOTE: The link button should hide an asp panel and show another one in code behind.