Border nodes can be moved freely

[gcoutable]

Steps to reproduce

1. Create a Papaya studio
2. Create a blank project
3. Create an empty model and create a papaya root element
4. Find sirius-components-collaborative component
5. Move the RequiredService

Expected result

No matter where the mouse pointer is, the RequiredService sticks to its parent

Actual result

RequiredService can move freely.
The next refresh seems to compute the RequiredService right abscissa to make it horizontally stuck to its parent.