Is your feature request related to a problem? Please describe.
With the release of patch 4.4.2 on Cataclysm Classic some UI changes with regard to the ExtraActionBarFrame and ExtraActionButton are coming.
It will be used for some raid encounters (Ultraxion and Madness) as well - if history is repeated - for some quests with special items.

Describe the solution you'd like
I would like support be added (back) to Dominos.

Describe alternatives you've considered
I have forked and revived BetterExtraActionButton from old (just in case) so I have a passing familiarity with changes from the first time around (ExtraAbilityContainer does not exist for example, as well ZoneAbilityFrame is not part of the current PTR)
I would much rather use Dominos for it though like I do for the EncounterBar and not have to add a separate actionbar mod :)

Additional context
There is a short window of opportunity to test and perhaps implement this feature in advance since the 4.4.2 PTR is currently live for raid testing over the weekend (31Jan-03Feb 2025) and it is a DMF week which should afford some chances to test without raiding.

Hmm, the DMF idea might be bust. I went to try the Ring Toss and Whack-a-Mole but they haven't moved them to the ExtraActionButton, so looks like actual testing will need a raid.

the latest release should have better support for the button in 4.4.2.

That looks like it will mostly work. I'm not sure it will retain the position properly though.

I think it's missing .ignoreFramePositionManager = true property on the ExtraActionBarFrame to avoid the client moving it back.
Edit: I'm blind, it's already done in ExtraAbilityBarModule:OnFirstLoad() apologies 😊

It might also need iterating UIPARENT_MANAGED_FRAME_POSITIONS and setting extraActionBarFrame = nil for other member frames so they don't try to adjust their position relative to the ExtraActionBarFrame when Dominos has taken over placement.

just tried in cata ultraxion and could not move the extra action button :(

was out of combat between attempts

Did you try to move it in-combat?

I had a chance to raid Ultraxion after all and Dominos moving the button worked fine.
11.0.9-cata

Moved it a little off-center like this, and that's where it showed up during the encoutner.

I think this can be closed. I don't want to discredit the other report but I've done Ultraxion 3 times and Madness twice and Dominos moves the extra action button properly.

Maybe it is a conflict with another UI move or actionbar-related addon, but Dominos handles it properly.