I just purchased Affinity Photo and am a transplant from Photoshop. I just failed my first experiment with the software, and I feel like an idiot.
I have an image with a single layer. I want to make a rectangular selection of pixels and copy/paste that into a new layer. So I do the following:
Open an image
Choose the Rectangular Marquee tool
Select a small area of the image
Edit>Copy
Create a new pixel layer and select it to make it active
Edit>Paste
These steps are identical to what I would do on Photoshop. However, instead of pasting the selection into the new layer, it duplicates the entire image into a new layer.
I tried pasting the selection into a new document, but it does the same - copies the entire image into a new layer in the second document.
All the marquee tools have the same behaviour. I have noticed that when I paste the copied selection into a new app, it's also pasting in the entire image layer.