chore: Sets DASHBOARD_VIRTUALIZATION feature flag to True by default (#26636)

RESOURCES/FEATURE_FLAGS.md

@@ -42,7 +42,6 @@ These features are **finished** but currently being tested. They are usable, but
 - ALLOW_FULL_CSV_EXPORT
 - CACHE_IMPERSONATION
 - CONFIRM_DASHBOARD_DIFF
-- DASHBOARD_VIRTUALIZATION
 - DRILL_TO_DETAIL
 - DYNAMIC_PLUGINS: [(docs)](https://superset.apache.org/docs/installation/running-on-kubernetes)
 - ENABLE_JAVASCRIPT_CONTROLS
@@ -65,6 +64,7 @@ These features flags are **safe for production**. They have been tested and will
 - ALLOW_ADHOC_SUBQUERY
 - DASHBOARD_CROSS_FILTERS
 - DASHBOARD_RBAC [(docs)](https://superset.apache.org/docs/creating-charts-dashboards/first-dashboard#manage-access-to-dashboards)
+- DASHBOARD_VIRTUALIZATION
 - DATAPANEL_CLOSED_BY_DEFAULT
 - DISABLE_LEGACY_DATASOURCE_EDITOR
 - DRILL_BY

UPDATING.md

@@ -36,6 +36,7 @@ assists people when migrating to a new version.
 - [26369](https://github.com/apache/superset/issues/26369): Removes the Filter Sets feature including the deprecated `DASHBOARD_NATIVE_FILTERS_SET` feature flag and all related API endpoints. The feature is permanently removed as it was not being actively maintained, it was not widely used, and it was full of bugs. We also considered that if we were to provide a similar feature, it would be better to re-implement it from scratch given the amount of technical debt that the current implementation has. The previous value of the feature flag was `False` and now the feature is permanently removed.
 - [26343](https://github.com/apache/superset/issues/26343): Removes the deprecated `ENABLE_EXPLORE_DRAG_AND_DROP` feature flag. The previous value of the feature flag was `True` and now the feature is permanently enabled.
 - [26331](https://github.com/apache/superset/issues/26331): Removes the deprecated `DISABLE_DATASET_SOURCE_EDIT` feature flag. The previous value of the feature flag was `False` and now the feature is permanently removed.
+- [26636](https://github.com/apache/superset/issues/26636): Sets the `DASHBOARD_VIRTUALIZATION` feature flag to `True` by default. This feature was introduced by [21438](https://github.com/apache/superset/pull/21438) and will enable virtualization when rendering a dashboard's charts in an attempt to reduce the number of elements (DOM nodes) rendered at once. This is especially useful for large dashboards.
 - [26637](https://github.com/apache/superset/issues/26637): Sets the `DRILL_BY` feature flag to `True` by default given that the feature has been tested for a while and reached a stable state.
 
 ### Potential Downtime

superset/config.py

@@ -441,7 +441,7 @@ DEFAULT_FEATURE_FLAGS: dict[str, bool] = {
     "DASHBOARD_NATIVE_FILTERS": True,  # deprecated
     "DASHBOARD_CROSS_FILTERS": True,
     "DASHBOARD_FILTERS_EXPERIMENTAL": False,  # deprecated
-    "DASHBOARD_VIRTUALIZATION": False,
+    "DASHBOARD_VIRTUALIZATION": True,
     "GLOBAL_ASYNC_QUERIES": False,
     "VERSIONED_EXPORT": True,  # deprecated
     "EMBEDDED_SUPERSET": False,