Index: kdelibs/kdeui/widgets/ktabbar.cpp
===================================================================
--- kdelibs/kdeui/widgets/ktabbar.cpp   (revision 715948)
+++ kdelibs/kdeui/widgets/ktabbar.cpp   (working copy)
@@ -302,6 +302,25 @@
 {
   if ( event->orientation() == Qt::Horizontal )
     return;
+  if ( event->delta() > 0 ) {
+    if ( currentIndex() == count() - 1 ) {
+      setCurrentIndex( 0 );
+    }
+    else {
+      setCurrentIndex( currentIndex() + 1 );
+    }
+  }
+  else if ( event->delta() < 0 ) {
+    if ( currentIndex() == 0 ) {
+      setCurrentIndex( count() - 1 );
+    }
+    else {
+      setCurrentIndex( currentIndex() - 1 );
+    }
+  }
+  else {
+      QTabBar::wheelEvent( event );
+  }

   emit( wheelDelta( event->delta() ) );
 }