Hah, my mom moves everyone's stuff around too! We are all mystified by it and it's a big family joke. (To be fair, she moves her own stuff around too, and can't find it half the time. My dad says she's like a squirrel who forgets where she stored her nuts

). I'm sure I've barked at her for it, too. It hurts her feelings and then I say sorry and then she forgives me. Sometimes she barks at me and I get over it too. The circle of life... Just say sorry and keep reminding her on her visits to not do that anymore. It won't help, but you can always try!