Hi Achille,
Thank you very much for the short video, it's very helpful to us! I found that this is a known issue in our database, unfortunately, it did not receive much attention due to the lack of reports. We will bring it to the developers to ask for a fix.
Unfortunately, there is no workaround in this case, other than to avoid panning/zooming when Displace function is activated.
Thank you once again for your report! If you have any further questions, feel free to ask me again!
Best regards,
Minh
Minh Nguyen
Technical Support Engineer
GRAPHISOFT