I’m trying to set the collection layout to 3 columns, but designer shows 4 (or more) items… It’s the same if I set the laout to 2 columns. Also… Items go outside of category container… but if I set layout to 4 items, then all 4 items is held withing the container.
The Collection list layouts work as intended when the Collection list display settings are kept at default. However, when you set the display setting to flex, you override the default layouts.
To control the layout, you either need to refrain from using flexbox and only use the layout settings of the collection list, or set wrap children in the flex settings and use, for example, percentage values for the width for the Collection items to control the number of items you want on each row.