diff --git a/lib/kcommondecoration.cpp b/lib/kcommondecoration.cpp
index 1a3e8238dc..d6d838e0b7 100644
--- a/lib/kcommondecoration.cpp
+++ b/lib/kcommondecoration.cpp
@@ -373,7 +373,7 @@ void KCommonDecoration::addButtons(ButtonContainer &btnContainer, const QString&
                       btn = createButton(MaxButton);
                       if (!btn) break;
                       btn->setRealizeButtons(Qt::LeftButton|Qt::MidButton|Qt::RightButton);
-                      const bool max = maximizeMode()!=MaximizeRestore;
+                      const bool max = maximizeMode()==MaximizeFull;
                       btn->setTipText(max?i18n("Restore"):i18n("Maximize") );
                       btn->setToggleButton(true);
                       btn->setOn( max );