Bug 311784 – GitHub code browser text selection and find broken with "Never use font sizes smaller" setting

• Component: Layout and Rendering
• Status: NEW

[Jon]

Created attachment 478975 [details]
Find interaction recording

When using GitHub code browser (say, at https://github.com/apple-oss-distributions/objc4/blob/fb265098298302243cd7eeaa1f63f0ba7786dd9a/runtime/NSObject.mm) text selection and find within the code block are both deeply broken.

Text selection is hard to start, and when it does work, it's often misaligned with the actual text, sometimes has visible gaps in the selection between lines, and will often select the wrong text. Like the find result, it seems to get out of sync with the visible content.

At the same time, the find selection is completely broken. While it can find text, and the selection rectangles may start aligned with the first result, they quickly break, becoming unaligned with the content. You can see this in the video.

STP Release 241 (WebKit 21625.1.12), macOS 26.4.

[Alexey Proskuryakov]

Thank you for the report! Strangely, I cannot reproduce this. I see some minor visual glitches (arguably slightly better in STP than in shipping Safari), but none of the vertical offset issues as in the screen recording.

[Jon]

Yes, Safari seems to work fine, with the same extensions and everything.

Looking at it again, it's the "Never use font sizes smaller than" setting, which I have set to 13. Turning that off and it seems to work fine. Toggling that setting I can see it fix itself in real time, and break when I turn it back on.

[Jon]

Shipping Safari is broken in the same way with the setting enabled, I just never synced that particular setting.

[Radar WebKit Bug Importer]

<rdar://problem/174884571>