[kcmkwin/kwinrules] Add explanatory text to placeholder messages

src/kcmkwin/kwinrules/package/contents/ui/RulesEditor.qml

@@ -44,25 +44,24 @@ ScrollViewKCM {
             NumberAnimation { property: "y"; duration: Kirigami.Units.longDuration }
         }
 
-        Kirigami.PlaceholderMessage {
-            id: hintArea
-            visible: rulesView.count <= 4
+        // We need to center on the free space below contentItem, not the full
+        // ListView. This invisible item helps make that positioning work no
+        // matter the window height
+        Item {
             anchors {
-                // We need to center on the free space below contentItem, not the full ListView.
-                // Setting both top and bottom anchors (or using anchors.fill) stretches the component
-                // and distorts the spacing between its internal items.
-                // This is fine as long as we have a single item here.
-                horizontalCenter: parent.horizontalCenter
+                left: parent.left
+                right: parent.right
                 top: parent.contentItem.bottom
                 bottom: parent.bottom
             }
-            width: parent.width - (units.largeSpacing * 4)
-            helpfulAction: QQC2.Action {
-                text: i18n("Add Property...")
-                icon.name: "list-add-symbolic"
-                onTriggered: {
-                    propertySheet.open();
-                }
+            visible: rulesView.count <= 4
+
+            Kirigami.PlaceholderMessage {
+                id: hintArea
+                anchors.centerIn: parent
+                width: parent.width - (units.largeSpacing * 4)
+                text: i18n("No window properties changed")
+                explanation: xi18nc("@info", "Click the <interface>Add Property...</interface> button below to add some window properties that will be affected by the rule")
             }
         }
     }
@@ -87,7 +86,6 @@ ScrollViewKCM {
             icon.name: checked ? "dialog-close" : "list-add-symbolic"
             checkable: true
             checked: propertySheet.sheetOpen
-            visible: !hintArea.visible || checked
             onToggled: {
                 propertySheet.sheetOpen = checked;
             }

src/kcmkwin/kwinrules/package/contents/ui/RulesList.qml

@@ -59,6 +59,7 @@ ScrollViewKCM {
             anchors.centerIn: parent
             width: parent.width - (units.largeSpacing * 4)
             text: i18n("No rules for specific windows are currently set");
+            explanation: xi18nc("@info", "Click the <interface>Add New...</interface> button below to add some")
         }
     }