I copied and pasted a layer(s) from another Krita project. but they are not visible in the project I pasted them into.
They have an extra square in front of the layer. Why won't they show and what is that square?

You have what appears to be an empty vector layer, or maybe a layer with some very small objects in it.

Can you show the equivalent layer docker screenshot for the source image or, even better, post links to full screenshots of both images? As shown in your post, it's difficult to know what's supposed to be there.

The squares I see there are the square for the transparent layer thumbnail and the 'dot-square' icon that indicates a vector layer.

ahabgreybeard wrote:You have what appears to be an empty vector layer, or maybe a layer with some very small objects in it.

Can you show the equivalent layer docker screenshot for the source image or, even better, post links to full screenshots of both images? As shown in your post, it's difficult to know what's supposed to be there.

The squares I see there are the square for the transparent layer thumbnail and the 'dot-square' icon that indicates a vector layer.

So how can I make them visible? In the layers are a group of very small vector lines. Too small to be seen in the icon.

Are the source and the destination image the same size? Instead of copying layers, have you tried selecting the source objects then copy/pasting them to a destination layer to see if that works.

It would be very useful if you could post full screenshots of the source and destination images because that might give some clue as to what may be going wrong for you.