The spring inside the latch housing (IMG_1281) is broken and needs replacement. The latch (IMG_1280) no longer stays in the engaged position.
A quick learner from Watertown CT says:
July 17, 2020
I failed to state that this is a Pella roll screen door latch.
Bob from SWISCO responded:
July 20, 2020
See if the 83-115 Pella Latch matches what you need. If you need the entire handle set assembly, see if either the 83-123 or its opposite-handed counterpart, the 83-122, match up.