I have the Beta version of 7.0 - 14500.  I run SqueezeCenter on a server machine and access it from a desktop machine, and use the Fishbone skin.  When I drag a track from the playlist into the area above the playlist, the little green "Drag Here to Delete" box appears, but it comes up slowly.  If I drop the track by releasing the mouse button before the box is fully displayed, the "Drag Here to Delete" box is permanently corrupted.  Sometimes (depending on the precise timing or location of the drop, I think) the box gets tall and narrow and displays one word per line, sometimes it turns into just a small green box, and sometimes disappears completely.  Reloading the browser display fixes this.