Took a while to im­ple­men­t, but Bartle­Blog fi­nal­ly got a func­tion­al menu ed­i­tor:

Right now, it on­ly works with the mootool­s-based menu gad­get, but I will start work­ing on the ya­hoo menu ver­sion in a mo­men­t.

The on­ly thing not work­ing is the pre­view but­ton, be­cause it needs more sup­port on the back­end side.