I'm using Dreamweaver CC 2018 18.0 10136 Build
I don't get the error message when I open the Update Server Behavior, but if I try to set up the go to page with parameters it gets reverted back to:
$UpdateGoTo = "manage_pages.php?pageID=\" . echo((isset($_POST[\"RecordID\"]))?$_POST[\"RecordID\"]:\"\") . \""; and deletes your code.
I assume this is going to happen every time I create a form and need it to go back to the same page with the same parameters. Which I do a lot of.