pfSense

Almost any PHP error anywhere in the system will break the menu system. This issue should be resolved when the last of the PHP7 issues have been resolved.

Some packages, including arping, mtr, nmap, and iperf, all behave this way. They use XML pages but when the user clicks the submit button they have a custom <custom_add_php_command> which runs the command, dumps the output, and then calls exit. The abrupt end makes sure the "settings" are not saved since they are not supposed to be persistent, but it also appears to cause the JS for the menus to fail, and presumably some other issues that have not yet been noticed.

This isn't new behavior though, it's been this way for years and isn't related to PHP 7.x changes. The nmap package even includes a JS button to go back to the nmap page so the user has a way to navigate back.

There is probably a much better way to handle the requirements of these packages rather than the kludge they use now.

Since this is not a regression this can be kicked forward to future versions as needed.