Dishwasher and sump assembly

A dishwasher comprising:

• a tub at least partially defining a treating chamber with an access opening;
• a sump fluidly coupled to the treating chamber and defining a portion of the treating chamber;
• at least one sprayer emitting liquid into the treating chamber;
• a pump;
• a conduit fluidly coupling the sump to the pump and the pump to the at least one sprayer, thereby defining a recirculation circuit through which the liquid sprayed into the treating chamber collects in the sump and is pumped back to the at least one sprayer;
• a filter assembly provided in the sump and comprising a filter through which at least a portion of the liquid passes;
• an insert sleeve that is at least partially located within the filter assembly and defines an interior;
• and
• a displacement body comprising an air dome structure formed by a raised, hollowed out portion of the insert sleeve, wherein the air dome structure is contiguous with the insert sleeve to define the interior within the filter to raise a level of liquid within the sump.