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In multistore mode, some of the PrestaShop administration pages feature a prominent drop-down menu, titled "Multistore configuration for". This menu gives you the context of what you are doing: it enables you to set the shop or shop group to which the changes you are making are to be applied.
For instance, when creating a new product, the selection in this menu will determine whether the product will be available for all shopshops, only one shop group, or a single shop.
When editing a product, PrestaShop displays notifications to help you understand the scope of your changes. For instance, when editing a product while in the "Shop A" context, the notification will say "Warning, if you change the value of fields with an orange bullet, the value will be changed for all other shops for this product", with said orange bullet appearing on all the implicated fields, such as "Type of product", "Reference", the package's size, etc.
Likewise, if you change a product while in the "All shops" context or in the context of a shop group, some fields will be disabled: since they have a global impact, you cannot edit them. If you really need to edit this content, each field has a box that you can check to edit that field in all the shops under this context.
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