Pressing the menu button while touching a item will bring up the context menu.

• The context menu appears when you press the menu button while touching an item.
• “Delete” can be used on all items except switching camera.
  It puts away the item.
• “Lock” and “Visibility” settings can be used on a set of items.
  For details, refer to the page for each item.

When you lock an item, the item becomes ungrabbable, and it cannot be moved from the locked position.

The visibility is a setting that specifies whether an item is visible to cameras or not.
It is useful when you want an item to be “visible from the players inside the VR but invisible from the viewers of your stream”.
However, please note that not all the items have the option to change the visibility.