Delete parts of the object in inverted selection

[Sergiusz]

I have a selection created from a shape, which I then shift-inverted to get rid of parts of the object (marked with red arrows):

 

Instead it removes the whole object. How to do this?

[Alfred]

For pixel-based operations you need a ‘Pixel’ layer, but if you go to the Layers panel you’ll find that the selected layer is an ‘Image’ layer. Right-click it and choose ‘Rasterize’ to convert it so that you can delete selected pixels.

[Sergiusz]

@Alfred thanks for the hint!