Make Scrollbar collapse when not hovered

[RagibHasin]

No description provided.

[xStrom]

The scrollbar should also not collapse when there is a scroll in progress without hover, i.e. grab_anchor.is_some(). That would match Firefox behavior as well.

[PoignardAzur]

Thanks for the PR!

I'm not convinced it looks better, but the code change is idiomatic, and you're clearly more motivated to improve this code than me.

LGTM.

[PoignardAzur]

I don't like how many screenshots are changed here. These screenshots in particular are pretty heavy. Could we make hovered scrollbars the default in tests instead?

[xStrom]

In general, having a collapsable scrollbar is a style choice. So having it be an optional configuration of the widget makes sense. So if we want to reduce the screenshot churn, one option would be to make it configurable right now and then we can have it not be collapsable in those tests.

[RagibHasin]

We should migrate ScrollBar to use property system. Right now it does not do so at all. We can then have AutoCollapsible property that can be false by default.

What do you guys think?

[xStrom]

I think it can be a property, yes. I would also be fine with it being a simple bool on the struct just to get it working, if that is easier.

[PoignardAzur]

Forgot about the "user is grabbing the bar" case. That needs to be fixed before we can merge this.

[RagibHasin]

As we are concerned about screenshot churn and repo size bloat, #1773 also touches some of these screenshots (specifically of Portal widget).
If that behavior is desired then it would be better to merge these two PRs for better management of screenshot churn.

[RagibHasin]

Can we have a decision here, so that we can make progress?
@xStrom @PoignardAzur

[xStrom]

I don't think it needs to be merged with #1773 because of the screenshot churn. Once that is rebased I would assume zero screenshot changes in that one, because you can just do screenshots with autohide disabled.