Thanks for the response, Eli. Your understanding of the problem is correct. Your response both makes sense as well and aligns with what I have encountered in testing. Apologies for the extra information in my posts, but I clearly was confused in my understanding of how the properties of overlays interacted with each other and overlays between themselves.

After re-reading the documentation for an Overlay's `priority` property several times before I asked my question, I had a suspicion that it was only relevant on clashing properties that were declared across multiple overlays (i.e. Overlay Priority is a tie-breaker at the individual property level between the same properties, not at the overlay level between overlays: first line of the second paragraph). I was unsure though and thought the behavior I was experiencing was wrong/my understanding of the documentation was incorrect. The clarification and confirmation is appreciated.

The behavior around `display` taking precedence over `invisible` is surprising ... somewhat. I am not sure if that is documented anywhere or called out explicitly, I probably missed it if it was. However, stopping to think about the context, it seems to make sense and is logically what would be expected. There is still some doubt I have for certain scenarios and what makes intuitive sense but that is more about me needing to more clearly understand the display engine at a finer level than I currently do (`xdisp.c` here I come).

The cases presented thus far make sense, the first overlay processed essentially "wins" and if the starting positioning of an overlay is the same as another with each specifying either `invisible` or `display`, the `display` property value of whichever overlay "wins" (since the underlying text is _essentially_ invisible for all intents and purposes based on what/how `display` works, correct?). In other words, it could be thought of as `display` is `invisible` with benefits: `hide but show something else instead` OR the other way around, `invisible` is functionally equivalent to just `display ""`?

To solve my issue, I did end up specifying a `display` property on the `invisible` overlay with a condition similar to the condition applied for `invisible`: `display (if XYZ "")`. It worked, however, at the time it just felt "wrong" or "doing more than it should need to do for the effect desired" (if that makes sense).

Thanks for the explanation, clarification, and confirmations Eli!

Much appreciated,
David