- On RC page enable 'Group results by page' option
- Select the namespace filter, e.g. 'Talk', and select some highlighting.
- The changes to Talk pages won't be highlighted.
- Disable 'Group results by page' - all changes will be highlighted.
The same filter selection but without 'Group results by page' option
Note: the issue of Logged actions selected by namespace filter but not being highlighted filed separately as T174732: Logged actions selected by namespace filters cannot be highlighted