[WC-3390] DG2: improve virtual scroll behavior and height logic

packages/pluggableWidgets/datagrid-web/CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased]
 
+### Fixed
+
+- We fixed an issue where virtual scrolling prevented data loading when the grid had many columns, showing only the initial page of rows until the user performed a horizontal scroll or zoom.
+
 ## [3.9.0] - 2026-03-23
 
 ### Changed

packages/pluggableWidgets/datagrid-web/src/model/stores/GridSize.store.ts

@@ -135,5 +135,10 @@ export class GridSizeStore {
         const overflows = gridBody.scrollHeight > viewportHeight;
         this.gridBodyHeight = viewportHeight - (overflows ? 0 : VIRTUAL_SCROLLING_OFFSET);
         this.lockedAtPageSize = currentPageSize;
+
+        // Fallback: if locking didn't produce a scrollbar, load more rows
+        if (this.hasMoreItems && gridBody.scrollHeight <= gridBody.clientHeight) {
+            this.bumpPage();
+        }
     }
 }