kip wrote:
Yes you better glue them down they have been known
especially late at night to turn themselves,they do that kind of thing.

Hi...

Kidding aside, in the "olden" days, I used to often put
a tiny dab of plain old nail polish on a control. Just a
dot of it, covering a bit of the shaft...

This sort of locked it in place, yet was easily enough
cracked if need be. And if it was inadvertantly moved, it
was easy enough to put back precisely where it was by
matching up the cracked sections of paint.

Take care.

Ken