There is a File Blame
feature, accessible by right-clicking the filename of an staged or unstaged file, that shows you the whole file along with info about who changed which line in which commit. It also allows you to show the state of the file for each commit listed on the left.
The feature you are asking for, to view more lines of context in a diff view (like you can set in gitk
, for example), does not exist AFAIK.
EDIT: As of Version 4.0.0, GK finally allows to view and edit whole files. See GK Release Notes.