Index: /trunk/src/VBox/Frontends/VirtualBox/src/widgets/graphics/UIGraphicsButton.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/widgets/graphics/UIGraphicsButton.cpp	(revision 42797)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/widgets/graphics/UIGraphicsButton.cpp	(revision 42798)
@@ -103,8 +103,8 @@
             QColor backgroundColor = pal.color(m_fParentSelected ? QPalette::Highlight : QPalette::Window);
             QColor buttonColor = pal.color(QPalette::Window);
-            if (backgroundColor.black() > 128)
+            if (backgroundColor.lightness() > 170)
+                buttonColor = buttonColor.darker(160);
+            else
                 buttonColor = buttonColor.darker(95);
-            else
-                buttonColor = buttonColor.darker(160);
 
             /* Setup: */
@@ -138,8 +138,8 @@
             QColor backgroundColor = pal.color(m_fParentSelected ? QPalette::Highlight : QPalette::Window);
             QColor buttonColor = pal.color(QPalette::Window);
-            if (backgroundColor.black() > 128)
+            if (backgroundColor.lightness() > 170)
+                buttonColor = buttonColor.darker(160);
+            else
                 buttonColor = buttonColor.darker(95);
-            else
-                buttonColor = buttonColor.darker(160);
 
             /* Setup: */