diff --git a/UnityMcpBridge/Editor/Windows/UnityMcpEditorWindow.cs b/UnityMcpBridge/Editor/Windows/UnityMcpEditorWindow.cs
index 2cd61b20..14c9f5b6 100644
--- a/UnityMcpBridge/Editor/Windows/UnityMcpEditorWindow.cs
+++ b/UnityMcpBridge/Editor/Windows/UnityMcpEditorWindow.cs
@@ -58,10 +58,10 @@ private void OnEnable()
         
         private void OnFocus()
         {
-            // Refresh configuration status when window gains focus
-            foreach (McpClient mcpClient in mcpClients.clients)
+            if (mcpClients.clients.Count > 0 && selectedClientIndex < mcpClients.clients.Count)
             {
-                CheckMcpConfiguration(mcpClient);
+                McpClient selectedClient = mcpClients.clients[selectedClientIndex];
+                CheckMcpConfiguration(selectedClient);
             }
             Repaint();
         }