• Need the Sigil of Holding to render the item that is currently selected in the hand.
• Make the Sigil dye-able (Two layers, perhaps, one being the ink that isn't dyed and the other being the slate that is dyed?)
• When scrolling with the Sigil, the name of the sigil that is selected should appear whenever scrolling - currently disappears even if you haven't finished selecting.
• The Sigil should not be able to scroll to an empty slot.

For 2, we can just use IItemColor. If we change the border color to a light-ish grey and move it to a separate layer, we can just color that whatever the player has dyed it to.

4 should be simple to do, for 1, I had QOL idea if someone gets it working; to render the currently selected sigil in the inventory slot as a sub icon, kind of how the stack number is displayed, but with the selected sigil instead.

For 1, I was thinking something like just render the given sigil's texture, then a small glove on top of it (32x32 texture with a 16x16 glove at the bottom left or something)

Also, I attempted 4, but the way you wrote the sigil is just... confusing...

Was it? Couldn't you just edit the onMouseScroll() event hook to check for the next or previous slots for sigils and cancel if none are found?

Handling number 4 in the form of an additional UI element. https://streamable.com/9ksc

Still need to allow configuration of the location and orientation (vertical or horizontal)

That looks amazing, do need to figure out how to miniaturize that for my Sigil of Augmented Holding though...

Update.