Hi i'd like to see a few things all Opera browsers come over to firefox that'll be useful!
1) Indication of duplicate tabs when hovered over shown in the example Here.
2) Something similar firefox partly has but expanded on Opera has called "speed dials" that can be put in groups with a name and many sites can be put in said folders as shown Here with a animation for the tiles.
3) drop down menu to edit, open all tabs in same window, new or private window & delete shown Here.
4) Text box to add sites with some suggestions shown Here.
Hope these can get added by some chance to make firefox even better thanks!