Break Curve question

[anotherhoward]

In a closed object (a quadrilateral), I clicked "Break Curve" at a node. Surprisingly, when I move the broken node away from the object, the shape's color continues to fill the object even though its shape changed. Why is that?

I am using he latest version of Affinity Designer on my Mac.

[lacerto]

(...)

[GarryP]

To add a little to what Lagarto said above, all curves have a Fill even if you can’t see it, even straight lines made with only two nodes.
If you don’t want the fill you can remove it in a lot of different ways, depending on your personal preferences, but one simple way is to (1) go to the Colour Panel, (2) press the Fill icon and then (3) press the None icon, see attached image.