I'll add it back. There were a few issues as it would overlap with actions admins on the servers that were doing when using the middle-click button in cases that did not involve Static Lootables; I also initially added that as a debugging tool very early in the development and left it there, but quickly realized I wanted to make it easier for server owners to setup lootable definitions.
I'll add it back as a togglable option in the config (pressing R when in /sledit mode) in the next update. Didn't know people were using it, but I see the benefits on using it in other situations.