Some plugins use middle click in inventory's (Pick Block as its called in the key bindings) as an extra, and it doesn't seem to be registering to server, there is no console errors.

After speaking to the devs of the above plugins, it seems there may be an issue on Spigot's side.

Really sorry if this is already known but i couldn't find anything on it and this is my first bug report.

The three plugins that have been tried are

• ChestSort (+ API) 12.1.0 "Middle click for sort"
• Tweakin [1.17-1.18] 3.8.3 "Middle click for Shulker Box Preview"
• Command Panels | Custom GUIs 3.17.2.1 #2 "Middle click as part of gui Menu's"