If I edit several references (citations) in a row in VisualEditor, eventually the Edit button (in the References dialog) fails to work. I will attach a video of the problem in action.

The following normal sequence of operations succeeds for a while, but eventually step 2 fails.

1. Click the next reference. The references dialog appears.
2. Click the Edit button.
3. Edit the reference and make a change.
4. Click Apply Changes.

In the attached video, I click on references 10, 11, and 12 in succession and edit them successfully. But when I get to reference 13, I place the mouse pointer on the Edit button and click, but the References dialog just disappears. I then click reference 13 again and the Edit button works.

This problem is intermittent but happens frequently on my MediaWiki 1.34.1 setup.

It is possible that the page needs a decent number of references before the problem shows up. I tried a page with just 7 references but could not make the problem happen. My test page has 28 references.

It's also possible that the <ref> tags need to be all in a row, next to each other, with no spaces between, as in the video.