Good question. I guess it's related to accessibie content issues. I wonder about this since a while, did this significant subject matter vanish a little from the focus of general attention over the years.
So here is a page from Adobe on Creating accessible content in Adobe Animate CC . There are several mentions of Select Window > Other Panels > Accessibility. The page has been last published and obviously updated in September 2016. The Other Panel -> Accessibility is gone in the latest releases of Animate (v19.0, v19.1). I'm not sure when that actually happened and why?
However there are informations about Use ActionScript to create a tab order for accessible objects. Things like tabIndex, tabChildren() or tabEnabled(). But this is Actionscript 3. I'm not sure how these thing stand in Animate HTML5 Canvas. Perhaps the use of accessible Components is a possible approach.
Thanks for your respond, the latest Animate CC merge the stand alone accessibility panel into the properties panel (only in as3 document), it seems that the only workaround for HTML5 canvas is to use the DOM elements and place it on top of the canvas.
I feared already this might be the case. The place to add accessibility features should be actually a future EaselJS. Just similar like in AS3 it needs a few methods and properties like tabIndex, tabEnabled and the like for screen readers on interactive elements like buttons, dynamic texts and movieclips. Let's keep that in the pipeline.
Yes, assigning tab order with tabIndex does not work in ANCC canvas. I just tried to use a function to reassign tabs to elements for which I randomized the position and no joy!
This for one element should have worked but I suppose it is still not supported.
this.button.tabIndex = "1"; // does not work