I’ve looked and tested everything I could find. I basically need a custom control for a desktop application (WIN / MAC) which supports baaaaasic styling of text (Bold / Italic / links / list etc).
Everything I tested doesn’t do the job properly, or is focused on CODE editing, which is not what I am looking for.
I even considered buying proper wysiwyg solutions which means I would have to run it via htmlviewer, not sure if that will be a good idea.
Help / links appreciated… don’t care for purchased options, as long as it works 
You can make a basic text editor with the DesktopTextArea. Supporting the following functionality is easy:
- bold, italic, underline
- text color
- alignment
- copy/paste
- undo, redo
With some work, you can probably add links. I’m not sure about bullets, etc.
Following is an example we have developed that supports field tags for mail merging variable data.

There is also GitHub - atomiccity/FormattedTextControl: The Formatted Text Control for Xojo. I don’t have any experience with it so I cannot offer any comments.
I did one using the summernote javascript library, embedded inside a desktophtmlviewer
works fine, you can even insert pictures and tables
and it works on windows or linux as well…

Both look nice! Is there a chance to share this with me? Or I could pay for access?