Re: [fxtf-drafts] [filter-effects-2] Backdrop filters should not use BackgroundImage

I just wanted to quickly add a comment about the limitations of stopping backdrop-filter at an isolation boundary. It seems like there may be some misconception about how that limits what gets filtered. Please see [this jsbin](https://jsbin.com/viqolif/2/edit?html,output), which shows a dialog element floating over the top of (and filtering) all other elements on the page. The dialog is first in the DOM hierarchy, and the other elements include several nested stacking contexts. The point is that the stacking context limitation only applies if the backdrop-filtered element itself is nested inside a stacking context for some reason. As long as it sits outside, everything behind it on the page, including other stacking contexts, gets filtered. See also, https://www.apple.com - they use exactly this DOM structure for the nav bar at the top. I'd be very interested to see examples where the backdrop filtered element **needs** to be inside a stacking context for some reason - i.e. what type of effect isn't possible with the proposed isolation behavior?

![jsbin example](https://user-images.githubusercontent.com/29559695/47677281-ef79d700-db7b-11e8-91b2-27e4a2d80a0d.png)

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Received on Monday, 29 October 2018 20:15:50 UTC