dishwasher repair to detergent cup

The detergent cup latch won’t catch and I need to replace, can you tell me how to take the old one off? The part I see does not look like mine; afraid it won’t seal.

Here are your parts.
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=GLD4100M15WW

What does your dispenser (Item 811 in Section 2) look like?
If you click on the parts picture a new page will open with more views, info and a Q&A section.