Make virtualization compatible with overflow:scroll on document/body. Fixes #37659

src/Components/Web.JS/src/Virtualize.ts

@@ -9,7 +9,11 @@ export const Virtualize = {
 const observersByDotNetId = {};
 
 function findClosestScrollContainer(element: HTMLElement | null): HTMLElement | null {
-  if (!element) {
+  // If we recurse up as far as body or the document root, return null so that the
+  // IntersectionObserver observes intersection with the top-level scroll viewport
+  // instead of the with body/documentElement which can be arbitrarily tall.
+  // See https://github.com/dotnet/aspnetcore/issues/37659 for more about what this fixes.
+  if (!element || element === document.body || element === document.documentElement) {
     return null;
   }
 

src/Components/test/testassets/BasicTestApp/VirtualizationTable.razor

@@ -18,6 +18,11 @@
     </tbody>
 </table>
 
+<style>
+    /* Represents https://github.com/dotnet/aspnetcore/issues/37659 */
+    html, body { overflow-y: scroll }
+</style>
+
 @code {
     List<int> fixedItems = Enumerable.Range(0, 1000).ToList();
 }