Rich Text Box how to highlight text block

Question

I need a certain portion of my text in RTB to be highlighted not in the sense of changing the font style/color, but in the sense of making a block selection with a particula

Answer 1

Here I have created CustomRichTextBox to achieve this.

The source code a long with scenario is explained here. If you interested then you can reuse this usercontrol directly without worry about much

Scenario

https://sites.google.com/site/greateindiaclub/mobil-apps/windows8/customwpfrichtextboxwithcolorchangeandhighlightfunctionality

source code:

https://github.com/boobalaninfo/CustomRichTextBoxWithHighligh