Use EditSourceX from PEM Editor / IDE Tools to open methods, etc
EditSourceX from PEM Editor / IDE Tools is an enhanced version of native EditSource, in that it updates the appropriate MRU list, does name change the case of the file name that is opened, and also allows for checking out of SourceControl.
If Thor is running and PEM Editor has been installed, the object to do this can be made accessible through a single line of code -- so, within only adding a few lines, these capabilities could easily be added to GF.
I would find this most helpful -- for both of the reasons stated above.
Actually, there is one final reason. If a form/class is already open when you double-click on it, native EditSource may not open the correct method if the current object in that form/class is one of the objects contained therein (such as a textbox within a form). EditSourceX handles this rare occurrence correctly.