Trigger to close an object when tab focus moves from it?
Please help! I've discovered yet another 508-related problem I've discovered. I have invisible buttons over fields in a screenshot that each display a small popup with a brief description. (The learner is invited to select each field to learn more.) I have multiple "clicks outside" triggers to hide the popups and return the buttons back to normal when the learner clicks away from those buttons, which work wonderfully with a mouse, but I'm unable to figure out how to replicate this behavior for a learner who uses a keyboard and screen reader. Such a learner needs to be able to navigate to a button, press Enter to display the popup, "read" the text (e.g. with a screen reader), and then when they press Tab to move focus from the popup, I want the popup to close. Everything up to closing the popup when they move away from it works; it's this last step I'm unable to figure out how to do. Right now, the popup just stays up, and eventually you have a bunch of popups persisting on the page with no way to close them with the keyboard.
I thought maybe Control Loses Focus would do what I want, but it doesn't seem to be designed for that kind of behavior.
I'm aware of the markers, but they create a lot of clutter when placed on top of a screenshot and the result, frankly, is ugly. It would be nice if the popup functionality of markers could be applied to the button functionality.
Another option is mocking up a little close button (X) in the corner, but this is an imperfect and undesirable solution, as it will require me to create even more triggers to display with the popups (because you can't trigger a group, only objects).
Other thoughts on how I can make this work? Is there some magic trigger or setting somewhere that will hide these things again once focus moves from them?
Thanks in advance for the advice.