Highlighting positions in textboxs

[glow360]

Hi Im new to VB.net and would like to know if it is possible to just highlight certain position of a TextBox or RichTextBox by dragging a square anywhere on the window? (even if the textbox has no text) refer to the image below...

I do not want 2 highlight entire lines, just for example 2 words on 2 different lines by clicking n dragging a square to cover the 2 words.

Thanks for any help given.

 

[jmcilhinney]

I would guess that you'd have to use the Windows API for that. How exactly I couldn't say but that's not standard behaviour for a TextBox or RichTextBox.