When Edit Mode is active, you can select the parts of the HMI you would like to configure. This will be the default way to work when editing your HMI. In this mode…
<aside> <img src="/icons/hand_gray.svg" alt="/icons/hand_gray.svg" width="40px" /> Keep in mind: When switching to this mode, hidden parts of your current page may appear, such as elements with a set Display Condition. This is intentional, so that you can configure all elements even if they might be hidden in the HMI later.
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Also make sure to learn about its counterpart, Test Mode (Preview Panel).