diff --git a/sidebar/package/contents/ui/CategoriesPage.qml b/sidebar/package/contents/ui/CategoriesPage.qml
--- a/sidebar/package/contents/ui/CategoriesPage.qml
+++ b/sidebar/package/contents/ui/CategoriesPage.qml
@@ -27,7 +27,8 @@
     id: mainColumn
     Component.onCompleted: searchField.forceActiveFocus()
 
-    header: Item {
+    header: Rectangle {
+        color: Kirigami.Theme.backgroundColor
         width: mainColumn.width
         height: Kirigami.Units.gridUnit * 2.5
         RowLayout {