diff --git a/kcm/src/resolutionslider.cpp b/kcm/src/resolutionslider.cpp
--- a/kcm/src/resolutionslider.cpp
+++ b/kcm/src/resolutionslider.cpp
@@ -53,6 +53,7 @@
     qSort(mModes.begin(), mModes.end(), sizeLessThan);
 
     QGridLayout *layout = new QGridLayout(this);
+    layout->setMargin(0);
 
     if (mModes.count() > 15) {
         std::reverse(mModes.begin(), mModes.end());