I fixed a similar issue with a Bryton GPS using the pin from a single speed chain. Put it in the slot, then filled around it with glue although I would do it with suguru now.
Yep; that's the one, a little prong of sorts touching ,or as near as I can get to touching, the button then sugru it in place sealing the hole at the same time.
Will let you know how I get on!
I fixed a similar issue with a Bryton GPS using the pin from a single speed chain. Put it in the slot, then filled around it with glue although I would do it with suguru now.