Each window has its own found set. It is difficult to "pass" the found set; other than a Copy All Records routine using the IDs, or a Loop to gather them, or a Custom Function made for this (there are a few). I kind of have to wonder, why not just do this on the original layout, since that is where you want to end up? I don't see much reason to do a popup window. The "search" field could be a global field in the header (which would allow criteria entry to work in Browse mode). You could attach a script trigger to it, to activate a Find script, or you say, a button to run it.
If you really want the popup window, you could just keep the popup window, close the original window, and rename the popup menu to the original window's name (or the file name, if only 1 window remains).
The reason for the additional popup window is to help isolate specific records for viewing / editing .. like a filter. If I have a 100 records in the database, only 10 maybe "Lions" and 5 "Bears" and so on. I am hoping to make this a standalone app so l am trying to create an easy way to filter the data and reduce the "working size" of the data set. This task can be done on the current layout by entering Find mode, location the field, selecting the entry, and perform Find. Just thought if I could label a button Filter and allow to Find specific records it would be easier. This is kind of like using the Data -> Filter -> AutoFilter in MS Excel ... Actually trying to replace using MS Excel with a real database like FMP -- the actual size of the MS Excel I would like to replace currently exceeds 45,000 entries ... or 45,000 records.
Thanks ... you've given me a few extra thoughts.