Thanks Walt, but floating and manually arranging really isn't practicable when reviewing half a dozen shots to select the best and discard the worst of a burst, and is a chore when setting up a clone. Arranging horizontal or vertical tiling and then navigating all simultaneously is a trivial exercise in Photo+ and its absence in Affinity Photo is a serious limitation. In a clone or repair, seeing where the source is, is essential. Without this feature Affinity Photo is a no-go for me.
The Power Tools application seems to be one of those "Win10 will download and install for your inconvenience" applications. I am only now trying Affinity because, in my opinion Win10 is, to be polite, unsatisfactory, and to run under Win7, Affinity requires that other so-called new and improved feature, Aero, a feature for which I have yet to find a use and which results in some very weak on-screen contrast for old eyes.
Sorry you weren't able to lead me to a, perhaps undocumented, feature