The sides and base were glued to keep everything together.
I left the top wall loose so that you could place handkerchiefs inside. Unfortunately, the top is too loose and can be lifted with a handkerchief.
Do you have any cool ideas for simple locks? I’m looking for some inspiration, they can be glued, of course I can cut the whole thing out again. I’m looking for some cool patents, because I have no idea how to solve it. I also have 5mm diameter neodymium magnets that I can use.
Instead of glueing the base, can you glue the top and side pieces together? The additional mass should allow the top to stay down as you remove tissues.
Then use magnets to align and secure the full top to the base.
I haven’t been able to come up with a way to lock a flat plane to the top of a box other than perhaps a pair of wire bails, one near each end, to capture the top. Flip them down to the side to open, flip them up over the top and they hold the top down. Something generally like this, just slightly in from the top of each short edge:
What I’d be more likely to do (which would require remaking it, of course) is to make the top an open-bottom decorated box that slides down over the bottom, an open-topped undecorated box. Then if you want holding, you can use something like a decently tight fit, magnets, detents, pins, or any other concept to add some sort of connectivity between the side faces.