Consider the following:

let f x = x
let g (x : int) = x
let a = f 1
let b = g 1

If you place the cursor on the f in the third line and get the type, you get 'a -> 'a. Expand that and you get int -> int (the text selection does not expand). Expand again to get int when the selection expands to f 1.

However, if you place the cursor on g in the fourth line and do the same, you get int -> int twice before the selection expands to g 1 and you get int. This may lead people to assume that the expand selection feature does not work properly if when they try it for the first time it seems to no-op.