Test case:

1. Drill down to any table, and right-click on the table and select "View/Edit Data..." | "Filtered Rows..."
2. Type in some valid query
3. Wait for your connection to be lost (note: there is NOTHING that indicates the connection is(n't) lost)
4. Click on the "Filter Options" button
5. Type in a new query

BUG: You can't click the Save button and there's no (apparent) feedback as to why not.

It turns out that if you subsequently re-execute the old query, then you'll get the message that the database connection was lost and then are offered to reconnect. Once you do that, then you can successfully edit the query, as expected.

This behaviour is shown in the attached screen capture video.

Expected behaviour:

Given that the Save button is disabled in the Filter Options, then clearly pgAdmin knows the connection is lost. So ideally, simply clicking on the "Filter Options" button would offer to reconnect you (same as re-executing the query), and once the connection is reestablished, bring up the Filter Options menu.

Less ideal would be to provide some feedback upon clicking the Save button saying that the connection was lost.