When you pick the variable name field it shows a drop down list with the variable names but for some reason for arrays it lists all of the indexes making it useless unless you start typing a name. When you only have a few variables it’s easier to pick from the list but the array elements make that impractical.
Honestly, I see little use for being able to select an array element from auto complete. You’re just typing a number. Most of the time you don’t even use an explicit number for the index. You are more likely to to use for each child or a variable. I can’t image scrolling down to index 13.
The indexes and any structures should appear in the list as you type a name and narrow down the list.