There's the classical and traditional layout on one side, and the americanized walmart-type supermarket layout. The difference is in the basic approach.

The traditional layout will have things laid out by kind - it would have bread and any pastry together, then milk and all dairy products together, then kitchen related stuff (cake molds, toothpicks, plastic glasses, salt shakers etc) together, with kitchen and then bathroom chemistry next to it (which would include, or border with, all the car-related chemistry, shoeshine, insect repellants, candles). Paperware would be on a separate group and would include all of serviettes, toilet paper, tissue paper, packaging paper, bordering with office/school supplies (notebooks, pencils). Nearby would be all the bags - paper bags, trash bags, freezer bags. Drinks would progress from mineral water to soda drinks, then beer, wine, strong stuff.

The americanized layout doesn't give a damn about the nature of the product, it cares about what is bought with what, so if you're buying shoelaces, it will park shoeshine and brushes nearby - assuming that if you're trying to maintain your shoes, you may want to be reminded of the other stuff you may find useful. So powdered sugar will not be with sugar, and plain brown chocolate won't be with chocolate - they'll be with cake making stuff, along with raisins, cocoa and birthday candles (which, again, won't be together with other candles). Tongs may be with flatware if they look like something you may use for salad, but may be with barbecue equipment if they look handy for turning steaks. Lidl is partially in this camp... on the fence, actually. Roda, OTOH, is firmly in the traditional camp.

I imagine the confusion among the patrons is larger than mine - I have already spent years learning the logic behind the american layout (if any), and it still took me years to learn where to look for sandwich bags (in the party supplies, not in the school supplies, not in paper products, not among other bags).

New thing (2018) in Lidl is that now they can have same thing in two places - house brand and the one favorite supplier's in the regular spot, and the week's featured brand at the end of the aisle. I actually asked a clerk in Lidl: if they had parmesan, where would it be - among cheeses, among the pastry (as it's used mostly for spaghetti), or among the spices? The answer: neither, they'd put it with specialty items in the far corner.