There might be a problem with the mouse handling in UROverview on the new editor.
With only URO active in Chrome or Firefox, when zoomed at level 0 (max), the mousedown & drag sends you scrolling wildly, instead of dragging.
Easiest to start this off, is to select one of your 'areas' in the tabbed pane so it zooms out max on the area. After this, the zoom bar's sync is also gone. Clicking Permalink will always zoom @ level 0, no matter where you zoom in using the mouse.
Can anyone else verify this behavior ?