It seems that the TAdvRichedit component will always allow the user to select and then drag-and-drop elements, even if it is in read-only state.
How can I prevent that behavior ?
Did you set AllowSelect = false?
No, I didn't.
Setting it does prevent accidental drag-and-drop (as a side effect) but it also prevent the user from selection and copying text.
Would it be possible to fix that behavior ?
We have fixed this. Next update will address this.