From OpenSCADAWiki
For the GEOMETRY CHANGING of the selected widget or group of them you can point the mouse cursor to a green dot of the selection representation and next move the dot whether by mouse, holding the left button, or by keyboard, pressing the arrow keys — the arrow keys clicking cause of the corresponding size changing at 5 pixels on 1x scale and holding the Shift key you get 1 pixel. You can perform the SCALE CHANGING of the selection in the same way but holding the key Ctrl or toggling of the size mode on the status panel right. The coordinates of individual widgets in the selection change according to the ratio of their position in this selection!