The RT object was one of the first major improvements in DE8. As the first object where you could store and display text with variable fonts, colours and formatting it was a major leap forward but as an early adaptation it has suffered from a lot of weaknesses.
We have now updated and it will now work more like a proper RT editor.
Attatched you will find a small app that showcase the RT object and also show how you can resize the object to fill the screen form dynamically.
The derivation we use (and the new function MoveObject) is: