diff --git a/scripts/setup/phpmyadmin_install.sh b/scripts/setup/phpmyadmin_install.sh
index 1d80d1f..4182561 100644
--- a/scripts/setup/phpmyadmin_install.sh
+++ b/scripts/setup/phpmyadmin_install.sh
@@ -353,8 +353,7 @@ function da_mysql_phpmyadmin_only_db(): string
     session_name($sessionName);
     session_id($sessionId);
     session_start();
-    $auth = $_SESSION['DA_MYSQL_PHPMYADMIN_AUTH'] ?? [];
-    $db = is_array($auth) ? (string)($auth['db'] ?? '') : '';
+    $db = (string)($_SESSION['DA_MYSQL_PHPMYADMIN_RESTRICT_DB'] ?? '');
     session_write_close();
 
     return $db;
@@ -515,6 +514,7 @@ session_set_cookie_params([
 ]);
 session_start();
 $_SESSION['DA_MYSQL_PHPMYADMIN_AUTH'] = $ticket['auth'];
+$_SESSION['DA_MYSQL_PHPMYADMIN_RESTRICT_DB'] = (string)($ticket['restrict_db'] ?? '');
 session_write_close();
 
 header('Cache-Control: no-store, no-cache, must-revalidate');
diff --git a/tests/phpmyadmin_install_test.sh b/tests/phpmyadmin_install_test.sh
index 1e2f849..d2e0e57 100644
--- a/tests/phpmyadmin_install_test.sh
+++ b/tests/phpmyadmin_install_test.sh
@@ -130,6 +130,7 @@ ONLY_DB="$(php -d session.save_path="$SESSION_DIR" -r '
   session_id("onlydbtest");
   session_start();
   $_SESSION["DA_MYSQL_PHPMYADMIN_AUTH"] = ["user" => "x", "password" => "y", "db" => "demo_target_db"];
+  $_SESSION["DA_MYSQL_PHPMYADMIN_RESTRICT_DB"] = "demo_target_db";
   session_write_close();
 
   $_COOKIE["DA_MYSQL_PHPMYADMIN"] = "onlydbtest";
@@ -140,6 +141,24 @@ ONLY_DB="$(php -d session.save_path="$SESSION_DIR" -r '
 [ "$ONLY_DB" = "demo_target_db" ] \
   || fail "config.inc.php only_db should be scoped to the SSO ticket's database, got: '$ONLY_DB'"
 
+# When no specific database was requested (the top-nav PHPMYADMIN button),
+# only_db must be empty so phpMyAdmin shows every granted database.
+ALL_DB_ONLY_DB="$(php -d session.save_path="$SESSION_DIR" -r '
+  session_name("DA_MYSQL_PHPMYADMIN");
+  session_id("alldbtest");
+  session_start();
+  $_SESSION["DA_MYSQL_PHPMYADMIN_AUTH"] = ["user" => "x", "password" => "y", "db" => "demo_landing_db"];
+  $_SESSION["DA_MYSQL_PHPMYADMIN_RESTRICT_DB"] = "";
+  session_write_close();
+
+  $_COOKIE["DA_MYSQL_PHPMYADMIN"] = "alldbtest";
+  $cfg = [];
+  include $argv[1];
+  echo $cfg["Servers"][1]["only_db"] ?? "(unset)";
+' "$CONFIG_INC")"
+[ "$ALL_DB_ONLY_DB" = "" ] \
+  || fail "config.inc.php only_db must be empty for an all-databases login, got: '$ALL_DB_ONLY_DB'"
+
 grep -Fq 'return [$username, $password];' "$SIGNON_SCRIPT" \
   || fail "signon script should return username/password only"
 php -d display_errors=1 -r 'set_error_handler(static function($errno, $errstr) { fwrite(STDERR, $errstr . "\n"); exit(9); }); $cfg=[]; include $argv[1]; include $argv[2];' "$CONFIG_INC" "$SIGNON_SCRIPT" \