[QuickSilver]

Maybe she's id'd the area she can go, but doesn't realize that she should be looking for pads.

Here's what I would try: next time she goes on the pad, blot some of her other pads with her pee and put those out. She may recognize where she's supposed to go by smell. You can put one in a plastic baggy and take it to work with you. I know that sounds kind of gross, but I've actually done this.

Also, you should limit her roaming area. When she goes on the pad, praise her extravagently and give her a treat. When she goes somewhere other than the pad, interrupt her and take her to the pad to finish up.

If she is having accidents you don't notice until after the fact, she needs to either be confined to a smaller area or be monitored more closely. I know this is easier said than done. Thor can go quick as lightning. I've seen him pee in literally 1/2 a second. He'll be walking along and his legs go wide for one stride, and boom, he's done. If you don't have your eyes right on him, you'll miss it.

I think that's why crates and xpens are so helpful training yorkies, because it's really easy to miss their accidents.