diff --git a/korganizer/koprefsdialog.cpp b/korganizer/koprefsdialog.cpp
--- a/korganizer/koprefsdialog.cpp
+++ b/korganizer/koprefsdialog.cpp
@@ -878,6 +878,7 @@
            "You can change the selected category color using "
            "the button below." ) );
   connect( mCategoryCombo, SIGNAL(activated(int)), SLOT(updateCategoryColor()) );
+  connect(mCategoryCombo, SIGNAL(currentIndexChanged(int)), SLOT(updateCategoryColor()));
   categoryLayout->addWidget( mCategoryCombo, 1, 0 );
 
   mCategoryButton = new KColorButton( categoryGroup );