Mom starting to "test out" buttons and switches all over the house?

Oh, this would be terrible. I don't know what you could do to keep her away from all switches and buttons in the house, particularly if she gets up at night. You could block off certain areas of the house that are most dangerous, e.g. the kitchen. You could move any problem appliances so they are out of reach. You could put a protective box around the thermostat and unplug the TV when it isn't in use. Mostly I think you would have to take this one day at a time and try to keep the dangerous things away from her -- removing stove knobs, shutting down gas lines when not in use. If these things don't work, you may find it easier to look at placement in memory care. I hope it goes well. Big hugs coming your way.

My autistic son is obsessed with buttons and switches- it enough to drive you crazy even without the danger element, which is huge. In the past I've had to take the knobs off the stove, duck tape switches and outlets and baby proofed cupboards. I was able to train most of his actions away from his obsession but that can be much harder with an adult with dementia since then lack the ability to learn. As suggested above, Rainman is never left alone for more than a few minutes - which helps but he is tricky and fast - so not a perfect solution. One thing that helps - but I don't know how it would go over with an adult with dementia - is I've bought Rainman a number of toys that have dozens of buttons and switches - all producing some sort of sound or light - and these toys do keep him occupied for a good length of time.

@JessieBelle - thanks for the suggestions, yes one day at a time and I am watching if this habit subsides or continues. We have already been weeding things down in the house, and arranging for supervision. Also looking at placement. She had a short stay at the hospital, and got more confused after that. I have been told that might die down or might continue at this new level. I just saw her opening up medicine bottles while at my house....oh dear indeed

Beethere, definitely pull the plug on the stove. Cover up the toaster; if she cannot see it, she will not play with it. Put child proof latches on cupboards and a gate at the stairs. Really she is not safe alone anymore. Until you find alternate placement, be sure that 911 knows her medical issues and how to get immediate contact with you. Soon you may see wandering off the property.