Just to add a note that I am seeing this too on my 9.0.5 version. With Chrome I see an outline where the image should be that gets filled after I contract and expand. With Firefox I don't see the outline or the normal arrow at all, but there is a link there (you have to hover over that area to see the pointer change).
Automated response: Issues with Wiki+ tree view layout
The tree view layout is incorrect since v9. Also the edit tree button has the wrong caption, and button captions should not show visibly on mouse-over (as the text on the button is already visible).
The tree view layout is incorrect since v9. Also the edit tree button has the wrong caption, and button captions should not show visibly on mouse-over (as the text on the button is already visible).