How can I get content from RichTextBlockOverflow (for example some text)? And maybe someone know can I set RichTextBlockOverflow invisible?
RichTextBlockOverflow doesn't have its own content, it shows overflow content from the RichTextBlock it is linked to. If you want to know what text shows in the RichTextBlockOverflow you can use ContentStart ContentEnd properties and extract text from the RichTextBlock using Select and SelectedText