add notice on what is supported

src/Umbraco.Web.UI.Client/examples/sorter-with-two-containers/README.md

@@ -1,5 +1,5 @@
 # Property Dataset Dashboard Example
 
-This example demonstrates the essence of the Property Dataset.
+This example demonstrates the how to setup the Sorter.
 
-This dashboard implements such, to display a few selected Property Editors and bind the data back to the Dashboard.
+This example can still NOT sort between two groups. This will come later.

src/Umbraco.Web.UI.Client/examples/sorter-with-two-containers/sorter-dashboard.ts

@@ -40,6 +40,7 @@ export class ExampleSorterDashboard extends UmbElementMixin(LitElement) {
 		return html`
 			<uui-box class="uui-text">
 				<div class="outer-wrapper">
+					<h5>Notice this example still only support single group of Sorter.</h5>
 					<example-sorter-group .items=${this.groupOneItems}></example-sorter-group>
 					<example-sorter-group .items=${this.groupTwoItems}></example-sorter-group>
 				</div>