Feature guide: Spectator fix - NEZNAMY/TAB Wiki

About

With the introduction of spectator gamemode in 1.8, players having it automatically appear on the bottom of tablist with transparent name and missing Yellow number. This feature cancels gamemode change packets to spectator gamemode, cancelling this minecraft feature.

Enabling

To enable this feature, open config.yml and set
do-not-move-spectators: true.

Configuration

allow-spectator-bypass-permission: false
When enabled, players with tab.spectatorbypass permission will see spectators the usual way despite this feature being enabled.

Additional notes

Note 1: Receiving information about going spectator gamemode allows players to clip through walls. Cancelling this on self would result in inability to go through walls. To avoid this, the information will be cancelled for every player except the one going spectator gamemode. Therefore, if you change gamemode to spectator, you will still see yourself on the bottom, but no one else will (unless bypass permission is enabled and someone has it).