The detergent dispenser is designed to release detergent into your dishwasher during the wash cycles.
When your dishwasher has gone through many cycles, it is not uncommon for the detergent dispenser to stick shut and not release the soap. When this happens, you must replace the soap dispenser so that your dishes are properly washed.
With your new dishwasher soap dispenser fitted and the door reassembled, your dishwasher is ready to be put into action once again.