Separate Local and Installed sections
You will find separate Local and Installed sections as you can see on the image below.
The Installed section at the bottom lists all your installed packages. These are read-only, meaning you can drag elements from them onto your page, but you can’t customize them there.
The Local section at the top lists your custom instances. This is your writable area, where you can add anything, customize them, sort them, group them.
If you often find yourself dragging an element from the Installed section to your page, only to make the same changes, you should copy the customized element to your Local section, so you don’t have to apply the same changes again and again.