There is no way to move the masked screen when it is in the rectangle function, since when we hold the ctrl the rectangle performs another function. To solve this, why not make the preview screen like you just hold it down with the mouse wheel to move?
To move a single Pan/Crop mask, right-click onto the mask's outline in the Pan/Crop working space, then select »Select - Path« from the context menu. Now you can move the selected mask in the Pan/Crop working space via left mouse dragging.
To move several Pan/Crop masks as a whole, right-click onto the Pan/Crop working space and select »Select - All« from the context menu. Now you can move the whole area with all the masks included in the Pan/Crop working space via left mouse dragging.
Controlling Pan/Crop properties like the masks in the regular preview window would be nice but my guess is that this is not possible by software design.
@Former user Yes, I'm talking about moving the screen. It should be able to move without having to leave the Rectangle Tool. With the Anchor Tool we can hold the ctrl to move the screen, however in the Rectangle Tool it is not possible to do this with the ctrl, since the ctrl already has another function for the Rectangle Tool. So the devs should modify as soon as possible this function for the mouse scroll, both for the Anchor Tool and for the Rectangle Tool, to follow the Video Preview pattern, which we can move with the scroll.