Hi,
I just updated Source Tree to 1.6.21.0 and left it on for approximately two hours. Not doing anything with it just left it open while checking the logs. The memory usage just went bananas. Peaked at 5.2gig before I had to force it down.
(tried to attach an image, but HTTP error)
I will keep it on again to see if I can reproduce it.
Regards,
James