Instead of dyeing the tinyblock with a gui, it would be more interesting to dye it directly with dye, like real wool.

Update: After playing around with tiny blocks more, the color mode idea is looking more attractive. When coloring a lot of blocks, having to select the color for each one is pretty cumbersome. However, with the introduction of the "Block Chopper" and the ability to make tiny blocks from nearly any block, including blocks that are already dyed, I may be scrapping the color selector entirely.

So, for now, I'm tagging this as low priority.

I think Block Chopper 4 the win :P

I wanted to avoid doing this because it will require storing color information in the item as well and introduces the potential of filling your inventory up with a bunch of colored tiny blocks. But, perhaps all that could be avoided if right clicking the tiny block with a dye colors it but doesn't consume the dye. Then, when you pick up the colored block, it will just revert to white.

Maybe, I'm just being lazy here, but I think this would be reasonable.

Goodbye little color picker. You served us well.

Hmmm... just had another thought after reflecting on my beloved little color picker. What if we have a color picker tool? You right click a colorable tiny block with the tool to get the color picker.

@dannydjdk I'm happy with that too.
Maybe in the future you could introduce a mode that makes it possible to pre-select a colour. (Click once in the air to select the colour and then click on an item to change the colour) but it is more convenient.

I'm happy with this solution, but since it doesn't match your request, I'll let you decide if you want to close this issue or state your objection.