draw outline in anti-aliasing mode, to prevent darker pixel in the corner.

kdecoration/breezedecoration.cpp

@@ -455,12 +455,13 @@ namespace Breeze
         if( hasBorders() && !s->isAlphaChannelSupported() )
         {
             painter->save();
+            painter->setRenderHint(QPainter::Antialiasing, false);
             painter->setBrush( Qt::NoBrush );
             painter->setPen( c->isActive() ?
                 c->color( ColorGroup::Active, ColorRole::TitleBar ):
                 c->color( ColorGroup::Inactive, ColorRole::Foreground ) );
 
-            painter->drawRect( rect().adjusted( 0.5, 0.5, -0.5, -0.5 ) );
+            painter->drawRect( rect().adjusted( 0, 0, -1, -1 ) );
             painter->restore();
         }