Hi again Bruno. In you example that you couldn't recreate the error, you didn't click at the end of the sentence after highlighting a few times, and use the space bar and then try and add more text and then try highlighting again. It definitely fails. In my system anyway using Delphi 10.3.3 and also Delphi 10.4.
I have just found out that it doesn't appear to have a problem when you press enter a couple of times so there is a blank line after the text. It only does it if you type some text without adding an extra line or two below.
In the english text you added there are a couple of blank lines at the end so it doesn't cause an error.
So at least I know now how to stop the freezing from happening.