diff --git a/clients/test/test.cpp b/clients/test/test.cpp
index 83768bfcb8..ac78965842 100644
--- a/clients/test/test.cpp
+++ b/clients/test/test.cpp
@@ -64,16 +64,16 @@ Decoration::MousePosition Decoration::mousePosition( const QPoint& p ) const
     
 void Decoration::borders( int& left, int& right, int& top, int& bottom ) const
     {
-    if( options()->preferredBorderSize() == BorderTiny )
+    if( options()->preferredBorderSize( factory()) == BorderTiny )
         {
         left = right = bottom = 1;
         top = 5;
         }
     else
         {
-        left = right = options()->preferredBorderSize() * 5;
-        top = options()->preferredBorderSize() * 10;
-        bottom = options()->preferredBorderSize() * 2;
+        left = right = options()->preferredBorderSize( factory()) * 5;
+        top = options()->preferredBorderSize( factory()) * 10;
+        bottom = options()->preferredBorderSize( factory()) * 2;
         }
     if( isShade())
         bottom = 0;
diff --git a/clients/web/Web.cpp b/clients/web/Web.cpp
index 6674e537ba..856a9f1098 100644
--- a/clients/web/Web.cpp
+++ b/clients/web/Web.cpp
@@ -69,7 +69,7 @@ WebClient::init()
   QFontMetrics fm(options()->font(isActive(), isTool()));
 
   // border size
-  switch(options()->preferredBorderSize()) {
+  switch(options()->preferredBorderSize( factory())) {
     case BorderLarge:
       borderSize_ = 8;
       break;
@@ -85,7 +85,6 @@ WebClient::init()
     case BorderOversized:
       borderSize_ = 40;
       break;
-    case BorderTiny:
     case BorderNormal:
     default:
       borderSize_ = 4;
@@ -605,6 +604,12 @@ bool WebFactory::reset(unsigned long changed)
   }
 }
 
+QValueList< WebFactory::BorderSize > WebFactory::borderSizes() const
+{ // the list must be sorted
+  return QValueList< BorderSize >() << BorderNormal << BorderLarge <<
+      BorderVeryLarge <<  BorderHuge << BorderVeryHuge << BorderOversized;
+}
+
 }
 
 #include "Web.moc"
diff --git a/clients/web/Web.h b/clients/web/Web.h
index 33476abc2a..1d59a3d5ff 100644
--- a/clients/web/Web.h
+++ b/clients/web/Web.h
@@ -120,6 +120,7 @@ namespace Web
       virtual ~WebFactory() {};
       virtual KDecoration* createDecoration( KDecorationBridge* );
       virtual bool reset( unsigned long changed );
+      virtual QValueList< BorderSize > borderSizes() const;
   };
 }
 
diff --git a/kcmkwin/kwindecoration/kwindecoration.cpp b/kcmkwin/kwindecoration/kwindecoration.cpp
index 5826533ef9..3e25e9cd8e 100644
--- a/kcmkwin/kwindecoration/kwindecoration.cpp
+++ b/kcmkwin/kwindecoration/kwindecoration.cpp
@@ -29,6 +29,7 @@
 
 */
 
+#include <assert.h>
 #include <qdir.h>
 #include <qfileinfo.h>
 #include <qlayout.h>
@@ -39,6 +40,7 @@
 #include <qvbox.h>
 #include <qlabel.h>
 #include <qfile.h>
+#include <qslider.h>
 
 #include <kapplication.h>
 #include <kcombobox.h>
@@ -55,6 +57,7 @@
 #include "kwindecoration.h"
 #include "preview.h"
 #include <kdecoration_plugins_p.h>
+#include <kdecorationfactory.h>
 
 // KCModule plugin interface
 // =========================
@@ -121,6 +124,13 @@ KWinDecorationModule::KWinDecorationModule(QWidget* parent, const char* name, co
 			i18n(  "Enabling this checkbox will show window button tooltips. "
 				   "If this checkbox is off, no window button tooltips will be shown."));
 
+        lBorder = new QLabel( buttonPage );
+        slBorder = new QSlider( Horizontal, buttonPage );
+        QWhatsThis::add( slBorder, i18n( "This slider shows all border sizes supported by this decoration." ));
+        lBorder->setBuddy( slBorder );
+        lBorder->hide();
+        slBorder->hide();
+        
 	cbUseCustomButtonPositions = new QCheckBox(
 			i18n("Use custom titlebar button &positions"), buttonPage );
 	QWhatsThis::add( cbUseCustomButtonPositions,
@@ -159,6 +169,7 @@ KWinDecorationModule::KWinDecorationModule(QWidget* parent, const char* name, co
 	connect( cbUseCustomButtonPositions, SIGNAL(clicked()), SLOT(slotSelectionChanged()) );
 	connect(cbUseCustomButtonPositions, SIGNAL(toggled(bool)), buttonBox, SLOT(setEnabled(bool)));
 	connect( cbShowToolTips, SIGNAL(clicked()), SLOT(slotSelectionChanged()) );
+        connect( slBorder, SIGNAL( valueChanged( int )), SLOT( slotBorderChanged( int )));
 //	connect( cbUseMiniWindows, SIGNAL(clicked()), SLOT(slotSelectionChanged()) );
 
 	// Allow kwin dcop signal to update our selection list
@@ -239,6 +250,52 @@ void KWinDecorationModule::slotSelectionChanged()
 	setChanged(true);
 }
 
+static const char* const border_names[ KDecorationDefines::BordersCount ] =
+    {
+    I18N_NOOP( "Border size: Tiny" ),
+    I18N_NOOP( "Border size: Normal" ),
+    I18N_NOOP( "Border size: Large" ),
+    I18N_NOOP( "Border size: Very Large" ),
+    I18N_NOOP( "Border size: Huge" ),
+    I18N_NOOP( "Border size: Very Huge" ),
+    I18N_NOOP( "Border size: Oversized" )
+    };
+
+int KWinDecorationModule::borderSizeToIndex( BorderSize size, QValueList< BorderSize > sizes )
+{
+        int pos = 0;
+        for( QValueList< BorderSize >::ConstIterator it = sizes.begin();
+             it != sizes.end();
+             ++it, ++pos )
+            if( size <= *it )
+                break;
+        return pos;
+}
+
+KDecorationDefines::BorderSize KWinDecorationModule::indexToBorderSize( int index,
+    QValueList< BorderSize > sizes )
+{
+        QValueList< BorderSize >::ConstIterator it = sizes.begin();
+        for(;
+             it != sizes.end();
+             ++it, --index )
+            if( index == 0 )
+                break;
+        return *it;
+}
+
+void KWinDecorationModule::slotBorderChanged( int size )
+{
+        if( lBorder->isHidden())
+            return;
+        setChanged( true );
+        QValueList< BorderSize > sizes;
+        if( plugins->factory() != NULL )
+            sizes = plugins->factory()->borderSizes();
+        assert( sizes.count() >= 2 );
+        border_size = indexToBorderSize( size, sizes );
+        lBorder->setText( i18n( border_names[ border_size ] ));
+}
 
 QString KWinDecorationModule::decorationName( QString& libName )
 {
@@ -298,7 +355,9 @@ void KWinDecorationModule::resetPlugin( KConfig* conf, const QString& currentDec
         else
             preview->disablePreview();
         plugins->destroyPreviousPlugin();
-                
+
+        checkSupportedBorderSizes();
+
 	currentName = styleToConfigLib( currentName );
 
 	// Delete old plugin widget if it exists
@@ -392,6 +451,13 @@ void KWinDecorationModule::readConfig( KConfig* conf )
 	for(i = 0; i < dropSite->buttonsRight.length(); i++)
 		buttonSource->hideButton( dropSite->buttonsRight[i].latin1() );
 
+        int bsize = conf->readNumEntry( "BorderSize", BorderNormal );
+        if( bsize >= BorderTiny && bsize < BordersCount )
+            border_size = static_cast< BorderSize >( bsize );
+        else
+            border_size = BorderNormal;
+        checkSupportedBorderSizes();
+
 	setChanged(false);
 }
 
@@ -414,6 +480,7 @@ void KWinDecorationModule::writeConfig( KConfig* conf )
 	// Button settings
 	conf->writeEntry("ButtonsOnLeft", dropSite->buttonsLeft );
 	conf->writeEntry("ButtonsOnRight", dropSite->buttonsRight );
+        conf->writeEntry("BorderSize", border_size );
 
 	oldLibraryName = currentLibraryName;
 	currentLibraryName = libName;
@@ -484,11 +551,31 @@ void KWinDecorationModule::defaults()
 	buttonSource->hideButton('I');
 	buttonSource->hideButton('A');
 	buttonSource->hideButton('X');
+        
+        border_size = BorderNormal;
+        checkSupportedBorderSizes();
 
 	// Set plugin defaults
 	emit pluginDefaults();
 }
 
+void KWinDecorationModule::checkSupportedBorderSizes()
+{
+        QValueList< BorderSize > sizes;
+        slBorder->hide();
+        lBorder->hide();
+        if( plugins->factory() != NULL )
+            sizes = plugins->factory()->borderSizes();
+        if( sizes.count() < 2 )
+            return;
+        slBorder->setRange( 0, sizes.count() - 1 );
+        int pos = borderSizeToIndex( border_size, sizes );
+        lBorder->show();
+        slBorder->show();
+        slBorder->setValue( pos );
+        slotBorderChanged( pos );
+}
+
 QString KWinDecorationModule::styleToConfigLib( QString& styleLib )
 {
         if( styleLib.startsWith( "kwin3_" ))
diff --git a/kcmkwin/kwindecoration/kwindecoration.h b/kcmkwin/kwindecoration/kwindecoration.h
index 9183ff8ac2..7d4ce788c0 100644
--- a/kcmkwin/kwindecoration/kwindecoration.h
+++ b/kcmkwin/kwindecoration/kwindecoration.h
@@ -38,6 +38,8 @@
 #include <kconfig.h>
 #include <klibloader.h>
 
+#include <kdecoration.h>
+
 #include "kwindecorationIface.h"
 
 class KComboBox;
@@ -45,6 +47,7 @@ class QCheckBox;
 class QLabel;
 class QTabWidget;
 class QVBox;
+class QSlider;
 
 class KDecorationPlugins;
 class KDecorationPreview;
@@ -57,7 +60,7 @@ struct DecorationInfo
 };
 
 
-class KWinDecorationModule : public KCModule, virtual public KWinDecorationIface
+class KWinDecorationModule : public KCModule, virtual public KWinDecorationIface, public KDecorationDefines
 {
 	Q_OBJECT
 
@@ -83,6 +86,7 @@ class KWinDecorationModule : public KCModule, virtual public KWinDecorationIface
 		// Allows us to turn "save" on
 		void slotSelectionChanged();
 		void slotChangeDecoration( const QString &  );
+                void slotBorderChanged( int );
 
 	private:
 		void readConfig( KConfig* conf );
@@ -95,6 +99,9 @@ class KWinDecorationModule : public KCModule, virtual public KWinDecorationIface
                 static QString styleToConfigLib( QString& styleLib );
 		void resetPlugin( KConfig* conf, const QString& currentDecoName = QString::null );
 		void resetKWin();
+                void checkSupportedBorderSizes();
+                static int borderSizeToIndex( BorderSize size, QValueList< BorderSize > sizes );
+                static BorderSize indexToBorderSize( int index, QValueList< BorderSize > sizes );
 
 		QTabWidget* tabWidget;
 
@@ -109,6 +116,9 @@ class KWinDecorationModule : public KCModule, virtual public KWinDecorationIface
 		QCheckBox* cbUseCustomButtonPositions;
 	//	QCheckBox* cbUseMiniWindows;
 		QCheckBox* cbShowToolTips;
+                QLabel*    lBorder;
+                QSlider*   slBorder;
+                BorderSize border_size;
 
 		QObject* pluginObject;
 		QLabel*  pluginSettingsLbl;
diff --git a/lib/kdecoration.cpp b/lib/kdecoration.cpp
index 407a4ae091..e251908aff 100644
--- a/lib/kdecoration.cpp
+++ b/lib/kdecoration.cpp
@@ -370,9 +370,13 @@ bool KDecorationOptions::showTooltips() const
     return d->show_tooltips;
 }
 
-KDecorationOptions::BorderSize KDecorationOptions::preferredBorderSize() const
+KDecorationOptions::BorderSize KDecorationOptions::preferredBorderSize( KDecorationFactory* factory ) const
 {
-    return d->border_size;
+    assert( factory != NULL );
+    if( d->cached_border_size == BordersCount ) // invalid
+        d->cached_border_size = d->findPreferredBorderSize( d->border_size,
+            factory->borderSizes());
+    return d->cached_border_size;
 }
 
 bool KDecorationOptions::moveResizeMaximizedWindows() const
diff --git a/lib/kdecoration.h b/lib/kdecoration.h
index 079b96955d..30e854779b 100644
--- a/lib/kdecoration.h
+++ b/lib/kdecoration.h
@@ -122,7 +122,8 @@ public:
         BorderVeryLarge, ///< Very large borders
         BorderHuge,      ///< Huge borders
         BorderVeryHuge,  ///< Very huge borders
-        BorderOversized  ///< Oversized borders
+        BorderOversized, ///< Oversized borders
+        BordersCount     ///< @internal
         };
 };    
 
@@ -208,9 +209,13 @@ public:
      * The preferred border size selected by the user, e.g. for accessibility
      * reasons, or when using high resolution displays. It's up to the decoration
      * to decide which borders or if any borders at all will obey this setting.
+     * It is guaranteed that the returned value will be one of those
+     * returned by KDecorationFactory::borderSizes(), so if that one hasn't been
+     * reimplemented, BorderNormal is always returned.
      * The changed flags for this setting is SettingBorder.
+     * @param factory the decoration factory used
      */
-    BorderSize preferredBorderSize() const;
+    BorderSize preferredBorderSize( KDecorationFactory* factory ) const;
 
     /*
      * When this functions returns false, moving and resizing of maximized windows
diff --git a/lib/kdecoration_p.cpp b/lib/kdecoration_p.cpp
index e25ab88932..19df15fe5b 100644
--- a/lib/kdecoration_p.cpp
+++ b/lib/kdecoration_p.cpp
@@ -27,23 +27,26 @@ DEALINGS IN THE SOFTWARE.
 #include <kconfig.h>
 #include <qpalette.h>
 #include <qapplication.h>
+#include <assert.h>
 
 KDecorationOptionsPrivate::KDecorationOptionsPrivate()
-{
+    {
     for(int i=0; i < NUM_COLORS*2; ++i)
         cg[i] = NULL;
-}
+    }
 
 KDecorationOptionsPrivate::~KDecorationOptionsPrivate()
-{
+    {
     int i;
-    for(i=0; i < NUM_COLORS*2; ++i){
-        if(cg[i]){
+    for(i=0; i < NUM_COLORS*2; ++i)
+        {
+        if(cg[i])
+            {
             delete cg[i];
             cg[i] = NULL;
+            }
         }
     }
-}
 
 void KDecorationOptionsPrivate::defaultKWinSettings()
     {
@@ -52,11 +55,12 @@ void KDecorationOptionsPrivate::defaultKWinSettings()
     custom_button_positions = false;
     show_tooltips = true;
     border_size = BorderNormal;
+    cached_border_size = BordersCount; // invalid
     move_resize_maximized_windows = true;
     }
 
 unsigned long KDecorationOptionsPrivate::updateKWinSettings( KConfig* config )
-{
+    {
     unsigned long changed = 0;
     QString old_group = config->group();
     config->setGroup( "WM" );
@@ -161,14 +165,16 @@ unsigned long KDecorationOptionsPrivate::updateKWinSettings( KConfig* config )
     QString old_title_buttons_right = title_buttons_right;
     bool old_custom_button_positions = custom_button_positions;
     custom_button_positions = config->readBoolEntry("CustomButtonPositions", false);
-    if (custom_button_positions) {
+    if (custom_button_positions)
+        {
         title_buttons_left  = config->readEntry("ButtonsOnLeft", "MS");
         title_buttons_right = config->readEntry("ButtonsOnRight", "HIAX");
-    }
-    else {
+        }
+    else
+        {
         title_buttons_left  = "MS";
         title_buttons_right = "HIAX";
-    }
+        }
     if( old_custom_button_positions != custom_button_positions
         || ( custom_button_positions &&
                 ( old_title_buttons_left != title_buttons_left
@@ -185,12 +191,13 @@ unsigned long KDecorationOptionsPrivate::updateKWinSettings( KConfig* config )
 
     BorderSize old_border_size = border_size;
     int border_size_num = config->readNumEntry( "BorderSize", BorderNormal );
-    if( border_size_num >= BorderTiny && border_size_num <= BorderOversized )
+    if( border_size_num >= 0 && border_size_num < BordersCount )
         border_size = static_cast< BorderSize >( border_size_num );
     else
         border_size = BorderNormal;
     if( old_border_size != border_size )
         changed |= SettingBorder;
+    cached_border_size = BordersCount; // invalid
 
     config->setGroup( "Windows" );
     bool old_move_resize_maximized_windows = move_resize_maximized_windows;
@@ -200,14 +207,27 @@ unsigned long KDecorationOptionsPrivate::updateKWinSettings( KConfig* config )
 
 // destroy cached values
     int i;
-    for(i=0; i < NUM_COLORS*2; ++i){
-        if(cg[i]){
+    for(i=0; i < NUM_COLORS*2; ++i)
+        {
+        if(cg[i])
+            {
             delete cg[i];
             cg[i] = NULL;
+            }
         }
-    }
 
     config->setGroup( old_group );
 
     return changed;
-}
+    }
+
+KDecorationDefines::BorderSize KDecorationOptionsPrivate::findPreferredBorderSize( BorderSize size,
+    QValueList< BorderSize > sizes ) const
+    {
+    for( QValueList< BorderSize >::ConstIterator it = sizes.begin();
+         it != sizes.end();
+         ++it )
+        if( size <= *it ) // size is either a supported size, or *it is the closest larger supported
+            return *it;
+    return sizes.last(); // size is larger than all supported ones, return largest
+    }
diff --git a/lib/kdecoration_p.h b/lib/kdecoration_p.h
index 80bbd2e251..b5e7cabce3 100644
--- a/lib/kdecoration_p.h
+++ b/lib/kdecoration_p.h
@@ -31,6 +31,7 @@ DEALINGS IN THE SOFTWARE.
 
 #include "kdecoration.h"
 #include <qwidget.h>
+#include <qvaluelist.h>
 
 class KConfig;
 
@@ -41,6 +42,7 @@ class KDecorationOptionsPrivate : public KDecorationDefines
         virtual ~KDecorationOptionsPrivate();
         void defaultKWinSettings(); // shared implementation
         unsigned long updateKWinSettings( KConfig* ); // shared implementation
+        BorderSize findPreferredBorderSize( BorderSize size, QValueList< BorderSize > ) const; // shared implementation
 
         QColor colors[NUM_COLORS*2];
         QColorGroup *cg[NUM_COLORS*2];
@@ -49,7 +51,7 @@ class KDecorationOptionsPrivate : public KDecorationDefines
         QString title_buttons_right;
         bool custom_button_positions;
         bool show_tooltips;
-        BorderSize border_size;
+        BorderSize border_size, cached_border_size;
         bool move_resize_maximized_windows;
     };
 
diff --git a/lib/kdecorationfactory.cpp b/lib/kdecorationfactory.cpp
index 1f9eaae59d..0d85b3c9d0 100644
--- a/lib/kdecorationfactory.cpp
+++ b/lib/kdecorationfactory.cpp
@@ -45,6 +45,11 @@ bool KDecorationFactory::supports( Ability )
     return false;
     }
 
+QValueList< KDecorationDefines::BorderSize > KDecorationFactory::borderSizes() const
+    {
+    return QValueList< BorderSize >() << BorderNormal;
+    }
+    
 void KDecorationFactory::addDecoration( KDecoration* deco )
     {
     _decorations.append( deco );
diff --git a/lib/kdecorationfactory.h b/lib/kdecorationfactory.h
index 0b3bdbe6a6..640f3c9b1d 100644
--- a/lib/kdecorationfactory.h
+++ b/lib/kdecorationfactory.h
@@ -62,6 +62,15 @@ class KDecorationFactory
 	 * Note that true should be returned only when really necessary.
 	 */
         virtual bool reset( unsigned long changed ); // returns true if the decoration needs to be recreated
+
+        /**
+         * Reimplement this function if your decoration supports more border sizes than
+         * the default one (BorderNormal). The returned list must contain all supported
+         * sizes, ordered from the smallest to the largest one. By default, only
+         * BorderNormal is returned.
+         */        
+        virtual QValueList< BorderSize > borderSizes() const;
+
         virtual bool supports( Ability ability );
 	/**
 	 * Returns the KDecorationOptions object, which is used to access