As an update to this there should be WB 6.3 and SKS 6.3 betas going up later today.
There are improvements to the tree view but the layers tab is also worth checking out.
Anything on a 64bit bug that was reproduced and forwarded to the developers? I haven't heard anything on it for about a month+ now. It had to do the address bar becoming largely over-sized with certain skins.