Frank M.

@carl123
Yes, I have now tried that out. One can go directly to adjustments and any adjustments are implemented in a new adjustment layer affecting just the selection. One can even just create a new empty pixel layer on top (having the selection active) and then do e.g. a flood fill on the new pixel layer and only the selected area will be filled. 
However, I feel the above behaviour for a selection done based on an image layer actually gives even more weight to my argument. If I can do adjustments or changes on the selection which goes to the new layer (either automatically or by creating a new, empty pixel layer first to work on that), it would seem logically consistent that "Layer" -> "Duplicate Selection" (Ctrl-J), should also duplicate exactly my "selection" from the image layer and put that very selection onto a new pixel layer, rather than create a new, additional image layer with the whole image and thus ignore my selection. 
The function is called "Duplicate Selection", and I have a "selection", so please duplicate my "selection", not the whole image.
I am sure after one gets used to it, the behaviour will be internalized and justified -- In a few months time, I will most likely have lost the fresh perspective of a new user and find myself berating and educating the new, inexperienced users on why selection works just the way it should on image layers :-). For now, however, my viewpoint is that this behaviour/wording is inconsistent and simply confusing and therefore should be corrected, even if not a bug that crashes the application or spoils the data in an image.
/Frank

Hi Walt,
Thanks for the clarification!
You are right in regards to what confused me. In particular, the fact that one can use the image layer as a basis for the paintbrush tool, i.e. the areas get selected based on the colours present in the image layer, although the selection cannot work on that very same layer. Even if selected areas exist separate from layers, it does seem very counterintuitive that one may select an area based on an image layer, but then one cannot apply move the selection to a new layer for manipulating it.
I will never make that mistake again, but for other, new users it would be much better if the "New from Clipboard" function just created a pixel layer right away, possibly with a setting to create an image layer, if one really wants that.
/Frank

Yes, I know. However, there is still a quite strong relationship between a canvas selection and layers in the sense that one most often would use a layer as the basis of a selection and not select blindly on a canvas with no layers. In my case, it was the paintbrush selection tool used on an image layer. This worked as expected with areas of the same colour near the paintbrush being selected. Thus, there must be some default rasterisation or conversion taking place for that to work? This is also why it seems so compelling, logical and pleasing that the "Layer" -> "Duplicate Selection" should continue to work the same way, using those same pixels that were the basis of the paintbrush selection process to be copied to a new pixel layer.
Right, I see that now.
I experimented with a document with many pixel layers, clicking on several of these (selectin them) while also having an active "marching ants" selection on the canvas. In this case, the "Layer" -> "Duplicate Selection" function copies the layers and does not make a new pixel layer with pixels from the canvas selection. This is also a perfectly logical way for it to work.
So I see now there are two possible and logical functions for this single menu-point.
Perhaps the best would be a new, separate menu-point "Layer" -> "Duplicate Canvas Selection" (inactive when there is no canvas selection). This function would copy the pixels to a new pixel layer. I know you will now say that image layers may have many different resolutions and there may be other layer types :-). However, again, there must be a basic or default pixel conversion or interpretation that combines the layers to show the combined document in AF (when all layers are set visible or the document is exported as a PNG) as well as form the basis of, e.g., the paintbrush selection process. Would it be so wrong for that pixel representation to be used as a basis together with the canvas "marching ants" selection to form a new pixel layer?
In any case, each menu-point would then have a clear, separate function, which is a good thing.
Unless, of course, you now tell me that there are other functions for these that I do not know about as a new user.
Thanks for taking the time to go over these things in AF. It has been very informative :-).
 
/Frank
 

Hi Walt,
Thanks for the clarification!
You are right in regards to what confused me. In particular, the fact that one can use the image layer as a basis for the paintbrush tool, i.e. the areas get selected based on the colours present in the image layer, although the selection cannot work on that very same layer. Even if selected areas exist separate from layers, it does seem very counterintuitive that one may select an area based on an image layer, but then one cannot apply move the selection to a new layer for manipulating it.
I will never make that mistake again, but for other, new users it would be much better if the "New from Clipboard" function just created a pixel layer right away, possibly with a setting to create an image layer, if one really wants that.
/Frank