Visual Studio: what is maximum size of code that will be copied to MS word/writer/etc with formatting?

Question

I need to copy code from almost all code files in my project into LibreOffice Writer document. And each file after copying from Visual Studio and pasting it into document has formatting and a bit of syntax highlighting. However, the last and the largest file with about 300 lines after pasting is just a plain text without any formatting. It's kind of weird... Why would Visual Studio not format that code while it did format all other code? Is it issue with Visual Studio or I just must do something?

If this info is needed - it's a WPF project and I'm trying to copy content of MainWindow.xaml.cs. There are other windows in project and nothing is wrong with copying their code

EDIT: I did solve initial issue by copying file in two steps, so at first I copied about 130 lines and then copied the rest code. It seems that >300 lines of code is too large to be formatted.

The question now is: what is maximum size of the code that will be copied with formatting?