Differentiate Main Component from instances by color
Although component instances are differentiated by a different diamond icon, I still find myself accidentally modifying instances when I mean to modify the main component.
It would be useful to more clearly differentiate component instances by using a different border color so it's more obvious that I'm looking at an instance rather than the main component.
Joseph Silva commented
Another option is to differentiate by border style – for example, solid for the main component and dashed or dotted for instances. This would be more accessible than color.
Could also be useful to differentiate the default component state from other component states. I make the same mistake with states; I think I'm globally modifying the component, but I'm just modifying one state.