Formatting bar doesn't work in GNOME Web (Epiphany)

[smithfred]

Steps to reproduce

1. Type text in the message box and select.
2. Click any formatting button on the formatting bar.

Outcome

What did you expect?

Formatting is applied.

What happened instead?

Text is deselected and cursor moves to the beginning of the line, without any formatting applied.

Additional info

• No error messages logged in browser console.
• GNOME Web is WebKit based; 40.3 uses WebKitGTK 2.34.1.

Operating system

Linux

Browser information

GNOME Web (Epiphany) 40.3

URL for webapp

app.element.io

Application version

Element 1.10.1, Olm 3.2.8

Homeserver

matrix.org

Will you send logs?

No

[t3chguy]

That is not a supported environment as per https://github.com/vector-im/element-web#supported-environments

[smithfred]

Similar issue previously on Safari (i.e. also WebKit): #15710

Can't test on Safari at the moment as I just get a blank screen when visiting https://app.element.io in that browser...

[t3chguy]

Can confirm it affects Safari

[t3chguy]

Regressed by matrix-org/matrix-react-sdk@2ee732b