MC 1.7.10
Forge:10.13.4.1614
Gregtech: 5.0.9.19
Adventure Backpack: 0.8c

Hi,
just posting this discovered issue I came across today, thought you might want know about....

Strange render issues with none standard tools placed in quick select slots(green slots) backpack.
In this case, Gregtech tools placed within backpack's quick slot will cause the following render issues;

1. Items that are stored in player's inventory will no longer render. NEI will not be displayed either
2. The tool (example Gregtech shovel) will not display adjacent to the tank, on the player's HUD. Instead the tool is rendered as default missing texture.
3. 3rd person and 3rd person front view, world will not render. Instead the only thing that appears to render is the sky texture. Sleeping in bed also has the same issue.
4. Tools will render either on/above the player's head or below the feet, within Inventory player's 3D model.

Quick fix is to remove Gregtech tools from backpack's quick slots. A possible long term fix is blocking such tools from been placeable inside those quick slots.