I have recently developed a concept in my mind to modularize the application a bit. Until now, the main view of the application was only one - the list of documents and the preview on the right. I have decided to include the application settings in the main application view as well (instead of a separate window as before). In the upcoming version, icons will appear in the top bar to switch between the document view and settings.
The image above is the current working version of the settings view. I hope that I will improve it significantly before releasing the newest version. In the future there are going to be more views like this one - the module with settings is basically a proof of concept and preparation of the application structure for more such views.