1923948 - "part" attribute removed for moz-button label when it was being used to transition opacity on expand/collapse of the sidebar

Status: NEW

(Toolkit :: UI Widgets, defect, P3)

Description

[Kelly Cochrane [:kcochrane]]

In bug 1902083, the part="label" attribute was removed from the label element in moz-button. We were already referencing that here in order to fade in/out the button labels when expanding/collapsing the button labels. This was only for tools/extensions that use moz-buttons, a secondary bug was made to address animating labels for vertical tabs here.

Hoping :tgiles can weigh in on what our best path forward is on this and if we want to remove the part="label" attribute, is there something else we could use to animate those labels in/out.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1902083

Comment 2

[Tim Giles [:tgiles]]

Hey :kcochrane, thanks for the NI! I discussed this with the team during our Friday open meeting. I don't believe there's a huge issue with restoring the part="label" to the text that you want to animate. We were trying to figure out some way to make this particular case less brittle (since me removing the part in the first place caused this issue), but dealing with nested shadow roots is tricky.

The main concern I have is that we'll have animations for the moz-button labels but not for the tab labels, which will look odd. As long as this bug and Bug 1914440 are landed in the same stack, then the previous won't be an issue for me. Because of this, I'm going to set this bug as being dependent on 1914440.

I'll also be curious about the performance costing of animating hundreds or thousands of these tab labels, but that seems like it'll be investigated in Bug 1914440.

Does this seem reasonable to you :kcochrane?

Comment 3

[Kelly Cochrane [:kcochrane]]

Yeah sounds good to me. I wrote up bug 1914440 separately, so that we could investigate the potential performance effects of animating a bunch of tab labels might be. Ideally we'd probably only want to animate the labels of tabs that were visible in the viewport. Thanks for taking a look :tgiles!

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1902083