Focus-appearance & decorative effects

Hi folks,

During the meeting we discussed adjusting the perception interpretation paragraph to ignore ‘extraneous’ effects like shadow/glow.

I’ve done a bit of checking in WCAG 2.1 for current definition, and tried to implement Gregg’s suggestion here:
https://github.com/w3c/wcag/pull/2632/files

That updates the note to:
“What is perceived as the user interface component or sub-component (to determine enclosure or size) depends on its visual presentation. The visual presentation includes the component's visible content, border, and component-specific background. It does not include <a>decorative effects</a> emanating from the visible component such as shadows or glow effects.”

The definition is then:
<p>effects added to an element that are outside of the element and if removed do not change the ability to identify the element</p>
<p class="example">Shadows or glow effects around a user interface control.</p>

The question that occurs to me is: Why isn’t a background/border a decorative effect?
I think the answer is: The border helps you identify the UIC, whereas a shadow doesn’t. Maybe?

I’d appreciate any comments/suggestions as soon as possible please, we’re almost at the (this) finish line…

-Alastair