Core Overlay does not close properly when tab is not focused

[anthonytordillos]

There seems to be an issue with closing core overlays when the tab is not focused. The overlay itself is not visible (opacity: 0), but both it and the core-overlay-backdrop still cover the page and prevent page interaction. The problem happens regardless of whether layered is set.

To reproduce, go to the core-overlay demo and open dev tools. In the console, paste:

var overlay = document.querySelector('html /deep/ #overlay');
window.setTimeout(function() { overlay.opened = true; }, 10000);
window.setTimeout(function() { overlay.opened = false; }, 20000);

Then switch tabs. Come back to the tab 20 seconds later and the improperly closed overlay and overlay backdrop block page interaction.

[NickBolles]

This is happening in my Angular app too. It seems to be from showing and hiding it too fast. But it happens completely randomly it seems. I am not changing tabs tho, so maybe its another issue, with the same end result, but maybe it is related.