1. Create a new library
2. Ensure that "Groups" are visible:
   
3. Create new Group "Test": Click on "Add group" (below), enter "Test" as name, click "OK"
   
4. Result: Group "Test" created, group "All entries" focused:
   

Expected result: Group "Test" focused:

This issue is very much about code reading and understanding how JavaFX and JabRef works. The fix itself probably will be three lines of code. The challenge is really: Which three lines and where to put these lines.