We should look at improving the comparison page for Diffusion.
The major thing is that the compare view currently shows a list of commits present on A but not B, but does not show the actual diff of source changes.
On GitHub, the UI looks like this:
We implement a similar UI to the "Commits" tab (not selected) but do not have an equivalent feature to the "Files changed" tab (selected).
I suspect this is probably outside the realm of "UI changes", although it's technically a UI change I guess?
