Fix regression

osu.Framework.Tests/Visual/UserInterface/TestCaseSearchContainer.cs

···
                 }
             }
 
+            public bool FilteringActive
+            {
+                set { }
+            }
+
             public IEnumerable<IFilterable> FilterableChildren => Children.OfType<IFilterable>();
 
             protected override Container<Drawable> Content => flowContainer;
···
                         Hide();
                 }
             }
+
+            public bool FilteringActive
+            {
+                set { }
+            }
         }
 
         private class SearchableText : SpriteText, IFilterable
···
                     else
                         Hide();
                 }
+            }
+
+            public bool FilteringActive
+            {
+                set { }
             }
         }
     }

osu.Framework/Graphics/Containers/IFilterable.cs

···
         /// Whether the current object is matching (ie. visible) given the current filter criteria of a parent.
         /// </summary>
         bool MatchingFilter { set; }
+
+        /// <summary>
+        /// Whether a filter is currently being performed.
+        /// </summary>
+        bool FilteringActive { set; }
     }
 }

osu.Framework/Graphics/Containers/SearchContainer.cs

···
             {
                 searchTerm = value;
                 var terms = value.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
-                Children.OfType<IFilterable>().ForEach(child => match(child, terms));
+                Children.OfType<IFilterable>().ForEach(child => match(child, terms, terms.Length > 0));
             }
         }
 
-        private static bool match(IFilterable filterable, IEnumerable<string> terms)
+        private static bool match(IFilterable filterable, IEnumerable<string> terms, bool searchActive)
         {
             //Words matched by parent is not needed to match children
             var childTerms = terms.Where(term =>
···
             //We need to check the children and should any child match this matches as well
             if (hasFilterableChildren != null)
                 foreach (IFilterable child in hasFilterableChildren.FilterableChildren)
-                    matching |= match(child, childTerms);
+                    matching |= match(child, childTerms, searchActive);
 
+            filterable.FilteringActive = searchActive;
             return filterable.MatchingFilter = matching;
         }
     }

osu.Framework/Testing/Drawables/TestCaseButton.cs

···
             }
         }
 
+        public bool FilteringActive { get; set; }
+
         private readonly Container content;
         private readonly TextFlowContainer text;
         public readonly Type TestType;
···
 
         private void updateVisibility()
         {
-            if (matchingFilter || !collapsed)
+            if (FilteringActive && matchingFilter || !collapsed)
                 Show();
             else
                 Hide();

osu.Framework/Testing/Drawables/TestCaseButtonGroup.cs

···
             set => Alpha = value ? 1 : 0;
         }
 
+        public bool FilteringActive { get; set; }
+
         public IEnumerable<IFilterable> FilterableChildren => buttonFlow.Children;
 
         private readonly FillFlowContainer<TestCaseButton> buttonFlow;