Target element handling (default UI connections)

In 4.20 Beta 1 the way the UI system treats connections with the UI-tag was changed in such a way that as of per 4.20 default UI-connections are required to only have a single tag (the ui-tag). Before that change, default UI-connections could have other tags in addition to the ui-tag.

The problem with the old behavior was that in certain asset set ups, the UI would select the wrong UI-connection (mistakenly taking a non-default ui-tag for a default one). While the assets in a vanilla game are supposed to not suffer these problems (aka: where the game used a default-ui-connection, the chosen ui-connection in the end was always the default one), it's possible for mods to have created/changed assets resulting in the wrong connection being used.

The actual player visible/notable effects are quite difficult to describe in detail, because they depend on several game states which are not linear to reproduce. Notable problems ranged from wrong or duplicated target elements having been displayed, cases where the wrong target was selected or others were not selectable at all up to less perceptible issues like timings where a target element changed were slightly off.

We don't expect that any mod out there actually ran into this problem though, but if you did and you expected the previous behavior, feel free to leave a comment here.

Note: This change is not documented in the UI-modding notes, since it's related to an asset definition change and not exactly a change on the UI-system.