Clearing the version selector on a dataset's detail page throws a TypeError #8342

What happened?

The "Choose a Version" dropdown on a dataset's detail page has a clear (×) button. Clicking it throws an uncaught TypeError and leaves the page half-cleared:

the main pane switches to "No version is selected"
but the header above it still shows the cleared version's file path and size
the file tree on the right still lists that version's files, and clicking one now does nothing
the version size, created date and Download button disappear
Picking a version again recovers the page, so nothing is lost. But the error should not happen, and clearing the selection isn't a meaningful action on a page whose entire content is one version.

Expected: no clear button, and no error if the selection is emptied.

The model detail page does not have this problem — its version selector has no clear button.

Before clicking × — the clear button in the version dropdown:

After clicking × — empty main pane, but the old file path and the file tree are still there:

The same moment with the console error (the console output is overlaid onto the page so it fits in one screenshot):

How to reproduce?

1. Open a dataset that has at least one version: Your Work → Datasets → click a dataset.
2. Go to the "Versions & Files" tab and open the browser console.
3. Hover the version dropdown under "Choose a Version" and click the × that appears.
4. A TypeError is logged, and the page ends up in the state above..

Version/Branch

1.4.0-incubating-SNAPSHOT (main)

Commit Hash (Optional)

246f7bc

What browsers are you seeing the problem on?

Chrome

Relevant log output

ERROR TypeError: Cannot read properties of null (reading 'dvid')
    at DatasetDetailComponent.onVersionSelected (main.js)