How will you approach to implement a WYSIWYG document editor in WPF?
This editor is going to be very similar to WYSIWYG html editors, but back-end data structures do not have to be html. Currently, I have a working version based on mshtml control implemented in c++ (this is pretty much like MS InfoPath). I'm seeking to take out the mshtml dependency from this tool, so using WPF WebBrowser control is a choice I want to avoid.
Basic features to support:
Probably not exactly what you are after, but you might like to investigate the FlowDocument support build into WPF as it supports a lot of what you are asking for: https://learn.microsoft.com/en-us/dotnet/framework/wpf/advanced/flow-document-overview