Extension stuck expanding an item

[snoski]

I have a 6MB json file. The tree populates in the sidebar just fine. I can see that there are 5 top-level items, and I can see the count of sub-items in each item. (Sorry if the terminology I'm using isn't correct.)

However, one of these items has 897 sub-items. When I try to expand that item in the tree, the extension just shows the light blue progress indicator at the top indicating it is working. It has been doing this for long enough that I'm starting to think the extension is frozen, not merely still working.

It is a somewhat complex file. Each of the 897 sub-items have several sub-sub-items, and some of those sub-sub-items have sub-sub-sub items. So I would understand if it took a little while to populate. However, I'm not even trying to expand all. If the top level is level 1, all I'm trying to do is see level 2. It doesn't seem like it should be taking this long.