Streamfield menu hides plus icons when closed with no elements.

[unexceptable]

By default Wagtail if you close a streamfield menu when there are no elements, you get left behind a small single plus icon:

Same in the case of a nested streamfield (although it looks awful):

With the clearstream there is no icon:

Same with the nested clearstream:

[hminnovation]

Yes, it's an annoying bug. Thanks for flagging. Will look in to how I can improve.