Hi Kovid,
've hit a wall because I've not worked with a large Python project of this nature before and I'm unable to run the development version to test my changes. I honestly would need some time with someone more experienced than myself to get my environment set up properly, and then demonstrate the iterative workflow used for Python that allows me to implement changes, run the dev version, and debug.
Would you or someone you know be willing to take some time with me to show me the workflow I can turn this into a PR and potentially be an infrequent contributor moving forward?
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While working on this I discovered a bug where highlights appear out of order in the pane (and exports) from the order in which they appear in the book. Here's a screeshot:

Any ideas on how to fix this?