How many times have you come across an EXSR and wondered where in the 10,000 statements it might be.
Wouldn't it be easier to just enter a G in the sequence number. Then, when you have finished viewing or editing that subroutine, press F12 to return to your starting point.
And if you have subroutines calling subroutines calling subroutines calling subroutines: no problems - just keep drilling down with G and returning with F12. (If you want to keep track of a particular location, see Bookmarks below)
Once in a subroutine, functions such as Top, Bottom, Find work within the subroutine boundaries.