Your comments

I agree with Penski.

Now SmartGit have group "Diff Tools" in "Preferences -> Tools" window where you can add new diff tool as external viewer (for example notepad++.exe) which will be used when you double click at file in Log. But it's diff tool and when you double click at file it opens window with two files in some temp directory: old and new version.

The question is: can you add possibility to open only one version (new) of file instead of two versions in Log window?