I've properly set-up my .htaccess to accomodate my ErrorDocuments. Testing mydomain.com/missing.html correctly triggers the ErrorDocument 404.
However, I'm seeing something that I've never seen with any other server (and I've configured quite a few).
The ErrorDocument directive doesn't work with PHP files. For example, mydomain.com/missing.php should trigger the same ErrorDocument as the .html example above, but instead, I simply get the message, "No input file specified.," suggesting that PHP is being passed the URL to execute before Apache checks to see that it's valid.
Proper behavior would be for ErrorDocument to work the same, regardless of the extension of the bad URL.
How do I correct this?