Thank you for looking at SRCTREE-8109 and for attempting to fix it in with the release of 4.2.10. I'm afraid however that the fix only kicks the "can" down the road.

Before the bug was fixed, I could only select 10 files out of a 100 (for example) in the diff file list on the left.

Now I can select the entire 100, but – the view on the right still only shows diff for only 10 files.

Easy steps to reproduce with an open source repository:

1. Using Sourcetree, clone Apple's Device Management Client Schema repository.
2. Make sure that a commit with many changes is selected. I used commit (`ed9aac4`).
3. Make sure that the file diffs table is set to a flat list (any of the two).
4. Click on any item in the file diffs table.
5. Press Cmd+A on the keyboard.
6. The diff view on the right displays diff for only a subset of the selected files.