When using commands that provide TAB completion options, pressing ESC should display expected arguments that provide hints at what the command accepts. However, this behavior is seemingly inconsistent.

Steps to reproduce:

1. Start typing "/tp" and press space. It will show tab suggestions for the command
2. Press ESC to back out of the suggestions list
3. Observe how command suggestions are shown
4. Now, try the same with /teleport. Type "/teleport", press space and press ESC when you see the tab completions
5. Observe how, despite /tp and /teleport providing the same completions and expecting the same arguments, the hints don't appear, and instead an error does

This behavior seems inconsistent and confusing to me. I'd expect both commands would produce the same result, given they take the same arguments. Moreover, whether or not a syntax error or the hints are shown seems to vary between commands.

For instance, typing "/give", pressing space, then pressing ESC to back out of username completions will show the expected arguments for that command, but then proceeding to the next argument (/give William278), pressing space, then pressing ESC at the list of items will present a syntax error.

Edit as of Minecraft 1.20-Pre2

This seems to have been partially resolved as part of the fix for MC-165562. However, this is only a partial fix.

To demonstrate this, typing /tp and backing out of the TAB suggestions now correctly displays the argument suggestions. However, typing /tp William278 and pressing space will display the error, despite there being valid additional arguments a user could pass to the command. In that case, typing a single character will then display the argument suggestions list.

At the very least, the "inconsistent between commands" part of this issue has been fixed as of Pre-2, as this behavior is consistent between /tp and /teleport; it was not before. It remains inconsistent between arguments.