Video: https://www.youtube.com/watch?v=tmDdmQ-pEAQ
Not too happy with the transparency stuff, especially not that it happens as soon as I start dragging. Another approach I could imagine is widget explorer moving out of the way when I hover it and then moving it back in but for that I would need a C++ plugin and probably X stuff. (Don't we have a Usability group in Phab?)