Assuming I guessed right on the column icon rule, the problem is that Polish doesn't clear the icon caches (or any other cache). I fixed this by adding a call to refresh_ids after line 532. My problem is that I don't know what to do with the resulting lines 534-536. Do they need to stay? They are updating the book details pane. As far as I can tell, refresh_ids does not do that update, so the lines should stay. Do you agree?
calibre

calibre is an e-book manager. It can view, convert, edit and catalog e-books in all of the major e-book formats. It can also talk to e-book reader devices. It can go out to the internet and fetch metadata for your books. It can download newspapers and convert them into e-books for convenient reading. It is cross platform, running on Linux, Windows and macOS.
For more information, see the calibre About page
Screenshots
Usage
See the User Manual
Development
Setting up a development environment for calibre
A tarball of the source code for the current calibre release.
Bugs
Bug reports and feature requests should be made in the calibre bug tracker at launchpad. GitHub is only used for code hosting and pull requests.
Support calibre
calibre is a result of the efforts of many volunteers from all over the world. If you find it useful, please consider contributing to support its development. Donate to support calibre development.
Building calibre binaries
See Build instructions for instructions on how to build the calibre binaries and installers for all the platforms calibre supports.