0. ALWAYS PROVIDE INFORMATION ABOUT MODLOADER AND MOD VERSION
   Modloader: NeoForge

Minecraft Version: 1.21.1

Travelers Backpack Version: travelersbackpack-neoforge-1.21.1-10.1.22

Pixelmon Version (if relevant): Pixelmon-1.21.1-9.3.6-universal.jar

1. Describe the bug
   When entering certain custom dimensions like Pixelmon’s Ultra Space, the backpack GUI disappears completely.
   The backpack button (B by default) also does nothing. It appears as if the backpack was removed.

However, upon relogging into the server, the backpack becomes functional again.
This happens consistently when switching into the Ultra Space dimension.

Additionally, the enableBackpackRestoring config option mentioned in other versions does not exist in the current version (10.1.22), making it impossible to restore the GUI automatically.

2. Steps to reproduce the bug
   Equip a Travelers Backpack.

Enter Pixelmon's Ultra Space dimension (via Ultra Wormhole).

Observe that the backpack GUI is gone and the hotkey does not work.

Disconnect and reconnect to the server.

Notice that the backpack GUI returns after relogging.

3. What is expected behaviour
   The backpack GUI should persist across dimension changes.
   If removed temporarily, it should automatically restore without requiring a relog.
   Additionally, the config option enableBackpackRestoring should be available (as in previous Forge versions).

4. Screenshots
   N/A — GUI disappearance cannot be captured meaningfully, but can provide logs if needed.

Provide log when disappearing happens, also check if you can reproduce the issue on singleplayer