This only occurs in internet 6 and internet 7, firefox is ok

If we create a tree structure over 7 levels deep in the admin interface, the rotating clock appears on the deepest folder and will not disappear.

If we navigate to other folders further up the tree structure, they too 'catch' the rotating clock and cannot be opened.

The entire content tree can disappear and will require the browser session to be closed and re-opened in order for it to appear again. The spinning clock however, will still remain on the deepest folder, rendering the tree menu unusable again.

Steps to reproduce

under the content structure or media tabs, create a folder within a folder within a folder until you reach a depth of 7 or 8 levels then attempt to traverse the tree structure, collapsing and expanding folders...