> For this (not taking into account whether it is a double click or  
> something else), I use the parse tree of the method, so it
> will be the closest message or variable at the click point.

I don't mean to be difficult, but I think this is a mistake.  Anyone who has
had the misfortune of using eclipse will know why.  A method comment says
"Returns a Frammis", and you can't bring up Frammis because its in a comment,
not part of the parse-tree.  Or, you are typing code outside of any
method-context (i.e., workspace, Transcript or TextMorph) and suddenly none of
the ecompletion tools work.  Unlike current Squeak, it becomes more like
eclipse, inconsistent and "modal".

Simple string-parsing, combined with Kent Beck's "Type-suggesting Parameter
Name" practice, has served me so well over the years, the above-examples all
work great.  With just a few lines of code, I'm now able to select, for
example, "aCollection" to bring up Collection, "inputFileStream" to bring up
FileStream, regardless whether I have a method-context or not.

Maybe a combination; i.e., use the parse-tree if you have one but String
interpretation if you don't or no results from the parse-tree..

 - Chris