Essling, Aspern and Stadlau are not districts. They are PARTS of the 22nd district. They shouldn't be shown on the map in the same way as the entire district.

Elsewhere in Vienna too, place=suburb is generally used for parts of districts, not the entire district. What may be confusing is that for most districts, there is a part of the district with the same name as the entire district, e.g. Floridsdorf or Liesing. This isn't true of the 22nd.