The rendering behavior when the alpha channel of the parent node does not affect the alpha of the child node, but affects the overall rendering result of this group of nodes, is well known. This is accepted in graphic editors, in web and mobile development.
I don’t see this rule true for objects and sprites, but it may be true for gui nodes. What do you think of it? Optional alpha-grouping?
My problem is fading the alpha of the complex nodes structure. For example, the gray bar here is the parent node and the pink bar is the child node.
By animating the alpha of the parent node, I get an unpleasant overlay effect and a not uniform animation of the opacity of the entire group. Look at stars and gray parts of bars that appear and disappear asynchrony.