fix issue with page down when running with vuu server data

vuu-ui/packages/vuu-table/src/useKeyboardNavigation.ts

@@ -247,9 +247,19 @@ NavigationHookProps) => {
             break;
           }
         }
-        requestAnimationFrame(() => {
+        // Introduce a delay to allow the scroll operation to complete,
+        // which will trigger a range reset and rerender of rows. We
+        // might need to tweak how this works. If we introduce too big
+        // a delay, we risk seeing the newly rendered rows, with the focus
+        // still on the old cell, which will be apparent as a brief flash
+        // of the old cell focus before switching to correct cell. If we were
+        // to change the way re assign keys such that we can guarantee that
+        // when we page down, rows in same position get same keys, then same
+        // cell would be focussed in new page as previous and issue would not
+        // arise.
+        setTimeout(() => {
           resolve([newRowIdx, colIdx]);
-        });
+        }, 35);
       }),
     [requestScroll, rowCount, viewportRowCount]
   );

vuu-ui/sample-apps/feature-filter-table/src/useFilterTable.tsx

@@ -176,8 +176,7 @@ export const useFilterTable = ({ tableSchema }: FilterTableFeatureProps) => {
     onAvailableColumnsChange: handleAvailableColumnsChange,
     onConfigChange: handleTableConfigChange,
     onFeatureInvocation: handleVuuFeatureInvoked,
-    // renderBufferSize: 50,
-    renderBufferSize: 0,
+    renderBufferSize: 10,
   };
 
   // It is important that these values are not assigned in advance. They