No loading progress bar whenever we create a new world or when the game is loading something

What's the problem: I don't see the green loading progress bar, the one you normally see when updating Minecraft, when creating a world, regardless of game modes.

What I expected: I expect myself to see a loading progress bar whenever I create a new world, and it should appear when it's building terrain and converting worlds.

How to reproduce:

1. You play Single Player.
2. Create a new World
3. (Optional) Set whatever world options you like.
4. Create.