diff --git a/clients/kde2/kde2.cpp b/clients/kde2/kde2.cpp
index f6187a2683..f73969b851 100644
--- a/clients/kde2/kde2.cpp
+++ b/clients/kde2/kde2.cpp
@@ -754,12 +754,12 @@ QString KDE2Client::visibleName() const
 	return i18n("KDE 2");
 }
 
-QString KDE2Client::defaultButtonsLeft()
+QString KDE2Client::defaultButtonsLeft() const
 {
 	return "MS";
 }
 
-QString KDE2Client::defaultButtonsRight()
+QString KDE2Client::defaultButtonsRight() const
 {
 	return "HIAX";
 }
diff --git a/clients/kde2/kde2.h b/clients/kde2/kde2.h
index 9b51b74fe5..b7e05e3a97 100644
--- a/clients/kde2/kde2.h
+++ b/clients/kde2/kde2.h
@@ -73,8 +73,8 @@ class KDE2Client : public KCommonDecoration
 		~KDE2Client() {;}
 
 		virtual QString visibleName() const;
-		virtual QString defaultButtonsLeft();
-		virtual QString defaultButtonsRight();
+		virtual QString defaultButtonsLeft() const;
+		virtual QString defaultButtonsRight() const;
 		virtual bool decorationBehaviour(DecorationBehaviour behaviour) const;
 		virtual int layoutMetric(LayoutMetric lm, bool respectWindowState = true, const KCommonDecorationButton * = 0) const;
 		virtual KCommonDecorationButton *createButton(ButtonType type);
diff --git a/clients/laptop/laptopclient.cpp b/clients/laptop/laptopclient.cpp
index 69e1e3bacb..28c17413c3 100644
--- a/clients/laptop/laptopclient.cpp
+++ b/clients/laptop/laptopclient.cpp
@@ -351,12 +351,12 @@ QString LaptopClient::visibleName() const
     return i18n("Laptop");
 }
 
-QString LaptopClient::defaultButtonsLeft()
+QString LaptopClient::defaultButtonsLeft() const
 {
     return "X";
 }
 
-QString LaptopClient::defaultButtonsRight()
+QString LaptopClient::defaultButtonsRight() const
 {
     return "HSIA";
 }
diff --git a/clients/laptop/laptopclient.h b/clients/laptop/laptopclient.h
index cd5fadad3e..cb6a507775 100644
--- a/clients/laptop/laptopclient.h
+++ b/clients/laptop/laptopclient.h
@@ -36,8 +36,8 @@ public:
     ~LaptopClient();
 
     virtual QString visibleName() const;
-    virtual QString defaultButtonsLeft();
-    virtual QString defaultButtonsRight();
+    virtual QString defaultButtonsLeft() const;
+    virtual QString defaultButtonsRight() const;
     virtual bool decorationBehaviour(DecorationBehaviour behaviour) const;
     virtual int layoutMetric(LayoutMetric lm, bool respectWindowState = true, const KCommonDecorationButton * = 0) const;
     virtual KCommonDecorationButton *createButton(ButtonType type);
diff --git a/clients/modernsystem/modernsys.cpp b/clients/modernsystem/modernsys.cpp
index 34bb85d60a..3de5315f3f 100644
--- a/clients/modernsystem/modernsys.cpp
+++ b/clients/modernsystem/modernsys.cpp
@@ -455,12 +455,12 @@ QString ModernSys::visibleName() const
     return i18n("Modern System");
 }
 
-QString ModernSys::defaultButtonsLeft()
+QString ModernSys::defaultButtonsLeft() const
 {
     return "X";
 }
 
-QString ModernSys::defaultButtonsRight()
+QString ModernSys::defaultButtonsRight() const
 {
     return "HSIA";
 }
diff --git a/clients/modernsystem/modernsys.h b/clients/modernsystem/modernsys.h
index b09ca184b6..685b8a5781 100644
--- a/clients/modernsystem/modernsys.h
+++ b/clients/modernsystem/modernsys.h
@@ -29,8 +29,8 @@ public:
     ~ModernSys(){;}
 
     virtual QString visibleName() const;
-    virtual QString defaultButtonsLeft();
-    virtual QString defaultButtonsRight();
+    virtual QString defaultButtonsLeft() const;
+    virtual QString defaultButtonsRight() const;
     virtual bool decorationBehaviour(DecorationBehaviour behaviour) const;
     virtual int layoutMetric(LayoutMetric lm, bool respectWindowState = true, const KCommonDecorationButton * = 0) const;
     virtual KCommonDecorationButton *createButton(ButtonType type);
diff --git a/clients/quartz/quartz.cpp b/clients/quartz/quartz.cpp
index 9a8a296e51..e4e287caa0 100644
--- a/clients/quartz/quartz.cpp
+++ b/clients/quartz/quartz.cpp
@@ -537,12 +537,12 @@ QString QuartzClient::visibleName() const
 	return i18n("Quartz");
 }
 
-QString QuartzClient::defaultButtonsLeft()
+QString QuartzClient::defaultButtonsLeft() const
 {
 	return "M";
 }
 
-QString QuartzClient::defaultButtonsRight()
+QString QuartzClient::defaultButtonsRight() const
 {
 	return "HIAX";
 }
diff --git a/clients/quartz/quartz.h b/clients/quartz/quartz.h
index 9a85587e5e..4dd3982741 100644
--- a/clients/quartz/quartz.h
+++ b/clients/quartz/quartz.h
@@ -69,8 +69,8 @@ class QuartzClient : public KCommonDecoration
 		~QuartzClient() {;}
 
 		virtual QString visibleName() const;
-		virtual QString defaultButtonsLeft();
-		virtual QString defaultButtonsRight();
+		virtual QString defaultButtonsLeft() const;
+		virtual QString defaultButtonsRight() const;
 		virtual bool decorationBehaviour(DecorationBehaviour behaviour) const;
 		virtual int layoutMetric(LayoutMetric lm, bool respectWindowState = true, const KCommonDecorationButton * = 0) const;
 		virtual KCommonDecorationButton *createButton(ButtonType type);
diff --git a/clients/web/Web.cpp b/clients/web/Web.cpp
index faa35e46cb..16ef53f1e6 100644
--- a/clients/web/Web.cpp
+++ b/clients/web/Web.cpp
@@ -55,12 +55,12 @@ QString WebClient::visibleName() const
     return i18n("Web");
 }
 
-QString WebClient::defaultButtonsLeft()
+QString WebClient::defaultButtonsLeft() const
 {
     return "S";
 }
 
-QString WebClient::defaultButtonsRight()
+QString WebClient::defaultButtonsRight() const
 {
     return "HIAX";
 }
diff --git a/clients/web/Web.h b/clients/web/Web.h
index b794c64949..fb6c136e5a 100644
--- a/clients/web/Web.h
+++ b/clients/web/Web.h
@@ -39,8 +39,8 @@ namespace Web
       ~WebClient();
 
       virtual QString visibleName() const;
-      virtual QString defaultButtonsLeft();
-      virtual QString defaultButtonsRight();
+      virtual QString defaultButtonsLeft() const;
+      virtual QString defaultButtonsRight() const;
       virtual bool decorationBehaviour(DecorationBehaviour behaviour) const;
       virtual int layoutMetric(LayoutMetric lm, bool respectWindowState = true, const KCommonDecorationButton * = 0) const;
       virtual KCommonDecorationButton *createButton(ButtonType type);
diff --git a/lib/kcommondecoration.cpp b/lib/kcommondecoration.cpp
index 31beec1a9d..c3f708a2ac 100644
--- a/lib/kcommondecoration.cpp
+++ b/lib/kcommondecoration.cpp
@@ -58,12 +58,12 @@ KCommonDecoration::~KCommonDecoration()
     delete m_previewWidget;
 }
 
-QString KCommonDecoration::defaultButtonsLeft()
+QString KCommonDecoration::defaultButtonsLeft() const
 {
     return KDecorationOptions::defaultTitleButtonsLeft();
 }
 
-QString KCommonDecoration::defaultButtonsRight()
+QString KCommonDecoration::defaultButtonsRight() const
 {
     return KDecorationOptions::defaultTitleButtonsRight();
 }
diff --git a/lib/kcommondecoration.h b/lib/kcommondecoration.h
index 43964f9c54..df47749907 100644
--- a/lib/kcommondecoration.h
+++ b/lib/kcommondecoration.h
@@ -138,13 +138,13 @@ class KWIN_EXPORT KCommonDecoration : public KDecoration
          * @see KDecoration::titleButtonsLeft()
          * @see KDecoration::titleButtonsRight()
          */
-        virtual QString defaultButtonsLeft();
+        virtual QString defaultButtonsLeft() const;
         /**
          * The default title button order on the left.
          * @see KDecoration::titleButtonsLeft()
          * @see KDecoration::titleButtonsRight()
          */
-        virtual QString defaultButtonsRight();
+        virtual QString defaultButtonsRight() const;
 
         /**
          * This controls whether some specific behaviour should be enabled or not.