aria-live alerts break in VoiceOver when switching tabs and leaving iframe

[jessegreenberg]

From https://github.com/phetsims/resistance-in-a-wire/issues/133. VoiceOver alerts do not get read if user switches Safari tabs, or leaves iframe with tab navigation. In http://jsfiddle.net/wLzu63s8/70/ we tried a few workarounds, none of them worked:

• hiding/unhiding alert elements when tab visibility changed with and without delay.
• removing/adding alert elements when tab visibility changed with and without delay.
• adding aria-relevant="additions" and aria-relevant="text"

Next step is to file a bug report with Apple.

[jessegreenberg]

Report submitted, removing assignment.

[jessegreenberg]

Apple responded to this one and asked for a "sysdiagnose". Trying to generate that now.

[jessegreenberg]

Attached, and replied to Apple on 2/28/18.