Fix Rendering Debugger going blank when search yields no results

Author: rolandk-unity

Packages/com.unity.render-pipelines.core/Editor/Debugging/DebugWindow.SearchFilter.cs

@@ -29,11 +29,13 @@ sealed partial class DebugWindow
         readonly Dictionary<DebugUI.Widget, WidgetSearchData> m_WidgetSearchElementCache = new();
         readonly List<TextElement> m_PanelHeaderTextElements = new();
         UIElementSearchFilter m_SearchFilter;
+        Label m_NoResultsLabel;
 
         void BuildSearchCache()
         {
             m_WidgetSearchElementCache.Clear();
             m_PanelHeaderTextElements.Clear();
+            m_NoResultsLabel = rootVisualElement.Q<Label>(name: "debug-window-no-results-label");
 
             foreach (var panelElement in m_RightPaneElement.Children())
             {
@@ -76,6 +78,9 @@ void InitializeSearchField()
                             tab.style.display = shouldShow ? DisplayStyle.Flex : DisplayStyle.None;
                         }
                     }
+
+                    bool noResults = !string.IsNullOrEmpty(searchString) && visiblePanels.Count == 0;
+                    m_NoResultsLabel.style.display = noResults ? DisplayStyle.Flex : DisplayStyle.None;
                 }
             );
             m_SearchFilter.InitializeSearchField("search-field");

Packages/com.unity.render-pipelines.core/Editor/Debugging/DebugWindow.uss

@@ -108,3 +108,8 @@
 .info-button:hover {
     background-color: var(--unity-colors-button-background-hover);
 }
+
+#debug-window-no-results-label {
+    display: none;
+    -unity-text-align: middle-center;
+}

Packages/com.unity.render-pipelines.core/Editor/Debugging/DebugWindow.uxml

@@ -15,6 +15,7 @@
         <ui:VisualElement name="debug-window-tab-container" class="">
             <ui:ScrollView horizontal-scroller-visibility="Hidden" view-data-key="debug-window-tab-container-scrollview">
                 <ui:VisualElement name="panels-inspector-insertion-element" />
+                <ui:Label name="debug-window-no-results-label" text="No results match your search." />
                 <ui:VisualElement name="scroll-buffer" />
             </ui:ScrollView>
         </ui:VisualElement>