Hi Pierre;
Yes, I reviewed a related ticket # 3614. I was able to replicate that RTE issue using the TX control. Swapping over to the TE Control though fixed that behavioral issue (not sure if you tried that). However, the TE control also has its Pro's & Con's vs the TX control in its slight behavioral differences. So you'll have to think about this & carefully test your App(s) if you do switch RTE handlers.
I also tested the example code in PB2019GA and found that using the TE control worked OK with the Test Case I was supplied with. However to my surprise, the TX control option in PB2019 even behaved differently than PB2017R3 using the same PowerScript code. :-(
However, this does point out that there are some minor TX control behavioral differences between PB2017R3 vs PB2019 even though theoretically, they should be the same control under-the-hood. My guess is that the behavioral changes might be around the PB "Wrapper" used to interface with the TX control. This ticket has now been transferred to Engineering for a closer look.
Please create a Support Ticket for your RTE issue as well so that Appeon can address these subtle issues around the TX control ASAP.
Regards ... Chris