Hi!
I remember when i first started using kdenlive a few (~5) years ago, there was a way to move the whole rotoscoping mask at once, either change the scale or the position of all the points at once. Is that still possible and I can't find it or did it just disappear ? I really found that useful.
Please tell me if i was dreaming

This is not possible. I note it as a feature request.

Thanks!

Opened a request: https://invent.kde.org/kde/kdenlive/issues/123

Moving all points in the mask is already implemented in 19.04. A cross is displayed at the center of all points that allows moving the whole mask. Resizing still todo.

Thanks for adding that cross. Unfortunately I'm afraid it's not sufficient, as I very often have it covered by the yellow line that appears to insert intermediate points, preventing me from grabing that cross even if I zoom up to the maximum level.
The best would be a keyboard binding like Alt+click or Shift+click to move the whole mask no matter where you click.
In Inkscape, paths and objects can be moved using the Alt key which locks the selection you have no matter where you click, preventing you from grabbing another object when you only want to move the ones you have selected. In our case the problem is not exactly the same but I think we could use the same key binding.