Related discussion: https://answers.atlassian.com/questions/52092/sourcetree-hides-history-while-refreshing

Conclusion: it would be good to be able to maintain the content of the log view while refreshing. Although we're being cautious here to try to avoid allowing a user to click on something that may no longer exist (history editing conditions for example), it would be great to find graceful ways to tolerate this kind of edge case rather than avoid it entirely with the heavier-handed approach.