When  enabling view permission for another user's research space, the  space is added to spaces combo box. At first the square caret is shown as the child of the newly visible space. 

1. Log into the owning user of a research space
2. Set the permissions for a research space (with at least some children) to a second user
3. Log into the second user
4. Use the combo box to select the newly visible space
5. The newly visible space is shown with a square caret
6. Switch to a different space using the combo box
7. Use the combo to select the newly visible one again
8. You will see the throbber display and it never stops
9. Wait a while
10. Refresh the browser
11. the triangle caret is displayed and subsequently the tree works fine, including populate subtrees as needed