With Epiphany, mouse hovers across the emails list in GMail is noticeably slower than Firefox

• Component: WebKitGTK
• Status: NEW ---

[Jeff Fortin]

I'm not sure if this WebkitGtk-specific, or Epiphany-specific, or anything of the sort, I'm just reporting what I'm noticing here with Epiphany 3.34.4 and WebKitGTK 2.26.4 on Fedora 31 (GNOME xorg session): Epiphany is noticeably slower than Firefox on Google web applications, particularly GMail.

The case here is fairly easy to reproduce: open a well-filled GMail inbox with Epiphany on one half of the screen, and Firefox (I'm currently using version 69, so not even the latest/greatest) on the other half of the screen. Note that my GMail inbox's density is set to "Compact", if that changes anything.

Then, move the mouse rapidly and repeatedly up and down across the messages list.
You will notice that the individual email items "highlights" are super smooth on Firefox, but laggy in Epiphany (the highlights trail with noticeable delay behind the mouse cursor).

[Jeff Fortin]

I will also add that scrolling with the mouse wheel in the messages list is also noticeably not smooth with Epiphany.

[Jeff Fortin]

The hover slowness is in big part related to the floating toolbar that appears on each message row which can be toggled off/on in https://mail.google.com/mail/u/0/#settings/general (I think the default setting is "On: Enable hover actions - Quickly gain access to archive, delete, mark as read, and snooze controls on hover."