diff --git a/dibi/Nette/DibiNettePanel.php b/dibi/Nette/DibiNettePanel.php
index da92cf27..fe2f041b 100644
--- a/dibi/Nette/DibiNettePanel.php
+++ b/dibi/Nette/DibiNettePanel.php
@@ -49,7 +49,7 @@ class DibiNettePanel extends DibiObject implements IBarPanel
 
 	public function register(DibiConnection $connection)
 	{
-		if (is_callable('Nette\Diagnostics\Debugger::enable')) {
+		if (is_callable('Nette\Diagnostics\Debugger::enable') && !class_exists('NDebugger')) {
 			class_alias('Nette\Diagnostics\Debugger', 'NDebugger'); // PHP 5.2 code compatibility
 		}
 		if (is_callable('NDebugger::enable')) {