A popped button! Of all the annoying things to go wrong on a tufted piece of furniture, this would be it. And the most common. Here’s what you do to fix the little problem.
Remove the lining very carefully so that you can just put it back on when you’re finished.
Investigate the problem. What the heck?? Are those freaking nails in this bench?? [Shaking my head in disbelief, people.]
You’ll need button twine and a large needle to replace your buttons.
Feed the button (you did save the buttons, right?) through the hole and make a slip knot with cotton felt, piping, fabric scraps, polyester – really anything except nails.
Pull as tight as possible, and tie twice to hold in place. Replace the lining.