The World's Premier Listing Software
for Birders and Naturalists!
Celebrating 22 Years Serving Birders
and Naturalists around the World!
Thanks for posting.
This has been fixed in Build 62 of version 4.1. Please upgrade to that version (Help | Internet: Check for an Update).
If you have the Checklist window maximized, as you obviously do, then the popup does not occur - as this forces it back to normal size.
The solution to have both, is to NOT maximize the Checklist Entry window, but instead, position it in the upper left of the main BD window, then drag and resize it down to the bottom right corner. This gives you the same size, and gives you the popup list of sightings on mouseover.
Let me know if I can assist further.