Fixed bug where debug_ajax was actually always on and could not be disabled; thanks to Gabriel Moya for reporting!

Author: stefangabos

Zebra_Database.php

@@ -5256,6 +5256,12 @@ private function _is_debugging_enabled() {
                 // debugging is enabled but needs to be logged instead of being shown on the screen
                 (is_array($this->debug) && empty(array_filter($this->debug, function($value) { return !(is_bool($value) || $value === 0 || $value === 1); })))
 
+            // AND
+            ) && (
+
+                // not an AJAX request, or an AJAX request and debugging AJAX requests is ON
+                !isset($_SERVER['HTTP_X_REQUESTED_WITH']) || $this->debug_ajax
+
             // AND
             ) && (