diff --git a/app/scantool/dialog_add.cpp b/app/scantool/dialog_add.cpp
index 5736ea83..1218c0d7 100644
--- a/app/scantool/dialog_add.cpp
+++ b/app/scantool/dialog_add.cpp
@@ -53,6 +53,7 @@ Dialog_Add::Dialog_Add(SANE_Handle devHandle, class MainWindow *mainWnd, const S
 
     m_scanParam = scanParam;
     ui->comboBoxButtonId->setCurrentIndex(m_scanParam.buttonId);
+    ui->comboBoxButtonId->setEnabled(false);
 
     m_formDeviceConfig = new Form_DeviceConfig(devHandle, m_scanParam.deviceConfigs, this);
     connect(this, SIGNAL(closeDevice()), m_formDeviceConfig, SLOT(on_closeDevice()));