Hi Friends,
I'm working on a very complex image, another attempt at photorealism, with many layers and sublayers. Here's a little snip of my Layers dialog for easy reference:



My understanding is that the sublayers lie below the parent layer (on the canvas, just like in the Layers dialog). Is that correct?

It is a grape, and the parent layer "colors" contains the base purplish colors, consisting of a few objects, mostly opaque. The sublayers "bluey" and "orangey" contain several smaller objects for some variations in color and hue that I see in the grape, some with transparency and some without. (And then in layers above these, I have all the little whitish areas (glaucus, in botany terms) along with highlights and shadows overlain.) I've already grouped and clipped all the objects in the sublayers ("bluey" and "orangey"), and now I'm ready to do the same for the parent layer ("colors"). I hide the sublayers to make it easier for me to select the objects in the parent layer. After grouping them, I unhide the sublayers, to find that the new group of objects in the parent layer are completely covering the objects in the sublayers. And I completely understand that when objects are grouped, they are moved from whatever their original positions might have been in the z-order, and placed all on the same single level of the z-order (I think in the level of whatever object was originally in the highest level). Logically, this is what I would expect. But then I realized that before I grouped them, I could see the objects in the sublayers.

I've already worked on this many hours, but it was only when I grouped them that I realized what is apparently happening. So now I start to experiment. With the new group of objects in the parent layer selected, I click "Lower to botton". To my surprise, now all the objects in the parent layer lie BELOW the objects in the sublayers! The Layer dialog indicates that it still is in the parent layer, but my eye shows me that it is below the sublayers. Yet indeed, if I Undo all the way back to before I grouped them, I can use Alt + click in some areas and select objects in the sublayers before I can finally select objects in the parent layer after a few more Alt + clicks.

When I first started to compose this message, I didn't think it was going to be a bug. I thought it was just something about Inkscape that I didn't understand. But I did find this in Launchpad, which sounds to me like this same, or at least similar problem: https://bugs.launchpad.net/inkscape/+bug/181488

So now, my question is whether I should add a comment to it?
All it says is that new objects added to sublayers are added on top of the parent layer. I wonder if it would be helpful to add a comment to the effect something like 'z-order of objects in parent layer can be changed across sublayers (moved below objects in sublayers)'? And maybe include a simple, sample file for reference? I see that that bug and some related ones are all circa '08 and '09, so perhaps a more current comment could be useful?

Also my experimenting reveals that the same is not true of the objects in the sublayers. I canNOT select objects in the sublayers, and use Lower to bottom and move them below the parent layer......hhhmm, I should say that after I use Lower to bottom to move the objects in the parent layer below those in the sublayers, I can't select objects in the sublayers, and move them below that. Neither can I move objects in sublayer "bluey" below objects in sublayer "orangey". (Or objects in "orangey" above objects in "bluey".)

So it seems it's only objects in the parent layer that can be moved across sublayers (below). Because of that, now I'm thinking this might not be the same bug. The bug states that new objects added to sublayers are added on top of those in parent layer. This problem is objects in parent layer which can be moved below objects in sublayers. As I was working, now I realize that indeed, when I added objects to the sublayers, they were placed on top of objects in the parent layer. But this is a slightly different, related problem. Maybe it should be a new bug? Or maybe it's something that I don't understand about Inkscape, after all??

This is on Win7, 64-bit, Inkscape 0.48.1 stable.

Thanks for your help

PS - I can make a simple, sample file to demonstrate, if you like. Just lmk Also, I've only test using Groups. I haven't tried with single objects, but assume it would behave the same.