diff --git a/src/qt_gui/main_window.h b/src/qt_gui/main_window.h
index b24620a90..d5f5fe060 100644
--- a/src/qt_gui/main_window.h
+++ b/src/qt_gui/main_window.h
@@ -81,7 +81,7 @@ private:
     // Status Bar.
     QScopedPointer<QStatusBar> statusBar;
     // Available GPU devices
-	std::vector<QString> m_physical_devices;
+    std::vector<QString> m_physical_devices;
 
 
     PSF psf;