Add control with inline math rendering capabilities

Current custom control would be cumbersome to use to produce paragraphs of text with inline math or longer flowing text with math as separate lines. See example below

http://marked2app.com/help/images/mathjax2.jpg

A control based on, e.g., a textbox, but with added handles such as [$, $] that uses the renderer would be a very useful addition.

EDIT

Did some research on this. Perhaps a using BlockUIContainer and InlineUIContainer inside a FlowDocument is a better way to go.