0. ALWAYS PROVIDE INFORMATION ABOUT MODLOADER (Fabric / Forge) AND MOD VERSION (For Example 1.19.2-8.2.10)
   Version : Fabric 1.19.2

1. Describe the bug
   Whenever i shift click a weapon to a backpack and the weapon and tool slots are empty the weapon or tool disapears and is inaccessible via the backpack but it is still visible when pressing ctrl on the backpack in the inventory. The only way i've found is by upgrading the backpack but passed netherite i don't know what to do.

2. Write steps to reproduce the bug
   Shift click a weapon or tool in an empty backpack inventory.

3. What is expected behaviour
   The weapon will disapear and only be visible from the player inventory by pressing the ctrl button and hovering on the backpack.

4. Screenshots (If applicable)

I think you are using outdated resourcepack, try clicking just above left upper bucket slot, it will show the tool slots, clicking again will hide them

Click on empty space above bucket slot

thank you for the quick reply and sorry for answering so late i tried it and it worked so thank you so much for the help :D !!!