How is it crazy? This behaviour always made sense to me.
Suppose you have a list:
- jaguar
- llama
- lorax
- manatee
Typing another 'l' would signal that you want the next 'l' element and move the cursor to 'lorax'.
To correct the position, you'd either have to hit backspace to go to the first 'l' item, press 'a' to move to the first 'lla' item (I'd hope... but if the control went to the first 'la' item - ignoring the second 'l' I typed, then I'd say the control has gone out of the ballpark)
Or maybe the user moves the cursor with one of the cursor keys to position the cursor on the desired item.
In practice, the amount of actual words that have the same first letter as the second letter is minuscule. Even words that have the same letter appearing twice in sequence.
It's just optimized for the most convenient scenario.
In the enable1.txt wordlist of 172,823 English words, there are 126 starting with a double letter, and those are largely the variations of oohs, aahs, oomphs, oozes, aardvarks, eels, eerinesses, and oodles of oocytes, oolites, oophytes and oologists near oomiaks.
Tested with some text files on Windows Explorer on Win11, typing lla actually moves from llama, to lorax and back to llama. I also put alpha on the list to see if it would jump to that, but it didn't.