Removing filter in sidebar brings user back to top

[klemay]

Steps to reproduce:

1. Open a web page or document that has a lot of annotations - you could even try this on the Hypothesis website home page.
2. Scroll down a ways and click on a highlight. The sidebar will be filtered to only show annotations associated with that text selection:
3. Click the "Show all" button to clear the filter

Expected behavior

The sidebar shows the annotation I was just looking at, with the preceding and following annotations being viewable by scrolling up or down in the sidebar

Actual behavior

The sidebar scrolls all the way back to the top. You have to scroll and manually find the annotation you were just looking at:

Notes

• This becomes more of a problem in heavily-annotated documents.
• This was brought to our attention via a support ticket: https://app.hubspot.com/contacts/6291320/ticket/304239687/

[klemay]

Notes from a conversation in Slack: This gets tricky when a user is filtering by search term rather than by document location. For example, visit this PDF and search the sidebar for the term "sequence". The sidebar looks like this:

When a user clicks "Clear search", where should we scroll the sidebar to? Should it be to the first search result?

...or would it be possible to have different behaviors for "Show all" vs "Clear Search"?