I made a post about this well over a year ago and it got zero attention. I refuse to believe I am the only one who finds this frustrating, so perhaps I explained it poorly.
I use Affinity Designer primarily for Web and Application design work.
Now often, I'll have a specific element, button, interface, whatever that I am working on and am not quite sure of the design yet. I'll draw up a couple of alternatives, and swap them out to see which I like best. It is this swapping that I find so annoying! Constantly having to find the one that is presently displayed, click it to hide it, then the one I want to show, and click to show it.
I wish there was a way to link specific items together as being a single unique 'item', that only one of will every display at a time. Then I can quickly and easily swap between all of them by simply clicking the check mark next to the one I would like to see.
Please consider working this as a feature into Affinity Designer. It is something I do all the time and find incredibly frustrating.