OpenToolsAPI challenge.

[Ali Dehban 25]

I'm making an IDE plug-in and I'm trying to draw something which is not a normal symbol or character.
I'm wondering if is it possible to draw something into the editor that can behave like this orange vertical line.
This is just highlighting, you can see it but you cannot modify or delete it like characters.

I'm aware that I have to catch the Editor and work with canvas probably to draw something like that but I cannot find any interface suitable to get the editor's canvas and draw something.

[Lajos Juhász 241]

It should be possible with Delphi 11.3 https://github.com/Embarcadero/RADStudio11Demos/tree/main/Object Pascal/ToolsAPI/Editor Demos