What to do when mom won’t follow directions?

Is this her house or yours?
Is this how she has always compiled her grocery list, or is it new behaviour?

One of my first memories of my MIL, whom I have now known for nearly forty years, was of my shocked surprise at seeing in her beautiful kitchen ranks of empty cans and packets on the window sill. Granted she did at least rinse them out first, but her method was the exact equivalent of your mother's. I too wondered what was wrong with a list. She liked doing it her way, was the answer to that.

(It was also the first time I'd encountered butter so old that even in the refrigerator it had gone past rancid and was actually properly off. Ohmygoodness. But she never ate it herself and therefore didn't care.)

So. If this is your mother's house and this is how she has always done it - you'll just have to learn to like it.

If it's your house, and you therefore have a legitimate claim to insist on your rules, can you compromise by putting a leak-proof plastic crate on top of the pie box? I suppose whether this could be tolerated must also depend in part how often you do the shopping.

Who has told you that mom doesn't have dementia?

When someone is suffering from dementia, you have to remember that "logic doesn't live here anymore." That's a great line that is often used in my caregivers support group to remind folks when like you, they are worried or upset over something that their loved one has no control over.
Instead of putting the trash in her chair(which I think is kind of mean actually)"so she has to deal with them before sitting down," why don't you just throw away what needs to be thrown away, and give your mom a break, as her brain is now broken, and logic doesn't live there anymore?
Perhaps it's time that you better educate yourself about Alzheimer's/dementia, as it will help you better understand what your mom is going through. Teepa Snow has some great videos on YouTube you can watch which are very informative, and the book The 36 Hour Day, is a great resource as well.
And of course, if caring for her is getting to be just too much for you, it may be time to look into placing her in the appropriate facility.

Your first post you said Mom has been tested but shows no signs of Dementia. You go on to say she is manipulative. I think you mention not bathing, to me this is a sign of something not right.

I really don't know what to tell you. You said in last post you do everything. Are you disabling her? For your sanity, just pick up the trash. Ignore what she does, maybe she is playing you.

If this is not working for you and she can afford it, find her a nice Assisted Living facility.

Depending how far along your mom is in her dementia journey, you may not be able to convince her to put something where YOU think it needs to go.

This particular behavior may not last long. It could be replaced by something different.

My mother now has a LIST of strange behaviors and “reasons” for doing them. What she SAYS may just be what comes out of her mouth. It may have no relationship to logic or reason at all.

Best wishes to you.

So, this sounds like she has dementia? If so, she can't follow directions. And will continue to do strange things like put trash by the front door. I'm sorry, but you are going to need to change your expectations of what your mom is capable. I know, from dealing with my mom, that it seems like, OMG WHY are you doing X??? Saying Y?? It often makes NO sense. But that's what dementia looks like. It doesn't make any sense.

Do some reading, find some tricks that are at her level. Don't try to reason or argue with her cuz it probably won't work.

Good luck.

Is this fairly new for her? She used to be able to keep a grocery list and or remind you another way?