When very many areas are loaded (100.000+) it is no langer possible to remove them, but in batches. It would be convenient to group the areas with a filter group, and to be able to delete all areas in this filter group at once.

Documentation:

https://previewsupport.tygron.com/wiki/How_to_remove_areas_with_a_filter#Removing_areas_with_a_filter_selection