Why does my Netbeans Xdebug session timeout after period of inactivity

Find php.ini and add the following line to the xdebug section.

xdebug.remote_cookie_expire_time = 3600

The number is the time in seconds for the cookie to remain active, which defaults to 3600 (1 hour). I set it to 36000 (10 hours), which works fine and encourages me to restart the process occasionally to free memory. You can set it to 0 (unlimited) if you want, although I found that caused odd freezes here and there.

Remember to restart Apache for the change to kick in.

This is probably related to your Apache-Configuration.

The probable cause is a configured timeout that defines after what period of time the server ends the process if nothing happens ... makes sense usually, but when debugging you might be just busy taking a look at something.

My setup is somewhat different from yours but maybe I can help you.

In the apache-folder /sites-available are located the files that configure your domain-related virtual hosts. Within the -Tags of your Domain and protocol I put

<IfModule mod_fcgid.c>
     AddHandler fcgid-script .fcgi
     IdleTimeout 300
     IPCConnectTimeout 20
     IPCCommTimeout 120
     IdleScanInterval 120
</IfModule>

That increased in my case the available period of time until the timeout would be triggered from 40 to 120 seconds.

Then (of course) restart your apache.

Maybe that helps.