Bug 213618 – [iOS] Event region briefly missing editable element after typing second character in question field on discussions.apple.com

• Status: RESOLVED
• Resolution: FIXED
• Component: Layout and Rendering

[Daniel Bates]

This is visually observable with the editable regions debug overlay enabled: defaults key WebKitDebugVisibleDebugOverlayRegions has bit 3 enabled.

Steps to reproduce:

1. Visit <https://discussions.apple.com>.
2. Type 'f' into the question field

Notice the field has purple overlay, which indicates that it's in the editable region.

3. Type 'f'.

Then the overlay briefly vanishes until search results come back.

[Daniel Bates]

Created attachment 402807 [details]
Test case

[Daniel Bates]

This also affects touch-action!

[Daniel Bates]

Created attachment 402808 [details]
Test case (shows it affects touch-action region too!)

[Daniel Bates]

How do I use ^^^ tests?

Easiest way is to just ensure WebKitDebugVisibleDebugOverlayRegions has TouchActionRegion and EditableElementRegion set. Here's the enum for reference:

[[

enum DebugOverlayRegionFlags {
    NonFastScrollableRegion = 1 << 0,
    WheelEventHandlerRegion = 1 << 1,
    TouchActionRegion = 1 << 2,
    EditableElementRegion = 1 << 3,
};

]]
<https://trac.webkit.org/browser/trunk/Source/WebCore/page/SettingsBase.h?rev=263316#L65>

[Daniel Bates]

<rdar://problem/62656131>

[Daniel Bates]

Note that bug #213564 will mitigate *this* bug (on https://discussions.apple.com), but that's only because the repro steps require focusing the search field. The root cause of this bug is that the event region is not updated for the foreground layer (if it exists) and could be triggered just like in the attached test case (0 interaction required!)

[Daniel Bates]

Created attachment 402810 [details]
Patch

[Daniel Bates]

Oops forgot to include the updated expected results for iOS...

[Daniel Bates]

Created attachment 402820 [details]
To land

[Daniel Bates]

Comment on attachment 402820 [details]
To land

Clearing flags on attachment: 402820

Committed r263538: <https://trac.webkit.org/changeset/263538>

[Daniel Bates]

All reviewed patches have been landed.  Closing bug.