diff --git a/ajax.php b/ajax.php
--- a/ajax.php
+++ b/ajax.php
@@ -67,14 +67,15 @@ function slate_permutate_json_success(ar
 
 if (isset($_REQUEST['school_registration_html']))
   {
-    if (!empty($_REQUEST['school']))
-      $school = school_load($_REQUEST['school']);
+    /*
+     * Since we're just an AJAX callback, ask school_load_guess() not
+     * to update $_SESSION with the school the user is using... And
+     * make sure that the frontend actually tells us what school the
+     * user is using ;-).
+     */
+    $school = school_load_guess(FALSE);
     if (empty($school))
-      {
-	$school = school_load_guess();
-	if (empty($school))
-	  slate_permutate_json_error('Unable to load any school.');
-      }
+      slate_permutate_json_error('Unable to load any school.');
 
     $page = page::page_create('');
 
diff --git a/scripts/displayTables.js b/scripts/displayTables.js
--- a/scripts/displayTables.js
+++ b/scripts/displayTables.js
@@ -49,7 +49,8 @@ function show_box_change()
  *   The jQuery object which should be populated with an error message
  *   or the result of loading.
  * \param data
- *   The data to send as a request.
+ *   The data to send as a request. The school and semester keys shall
+ *   automatically be set.
  * \param handler
  *   A function with the signature handler(target, data) which is called upon
  *   a successful response. There is a default handler which uses
@@ -70,6 +71,11 @@ function slate_permutate_load(target, da
 		target.html(data.html);
 	    }
 
+    if (!data.school)
+	data.school = slate_permutate_school;
+    if (!data.semester)
+	data.semester = slate_permutate_semester;
+
     if (jQuery.type(error_handler) == 'undefined')
 	error_handler = function(target, status_text, data)
 	    {