I have 2 staged files, I go to Actions -> Create Patch. I press the "Create Patch" button and I see the "Please select at least one file" message box. If I stage / unstage all files the dialog closes. I tried selecting files with CTRL, staging, unstaging them, nothing works.

The destination file does not exist, it shouldn't exist as it has to be created by SRCTREE however it's on a path that SRCTREE has access to (root of the repository).