Before you can copy, move, or delete points and lines for modifying the geometry of the furnace or the cartridge, you need to select them. Again, you have two ways for selecting objects, but in any case you have to use the right mouse button.
Note
For marking elements, be sure to use the
right mouse button. If you take the
left mouse button and move the mouse just a little bit, you
unintentionally zoom into the drawing. According to the extreme magnifying factor,
it seems as if the drawing vanished from your screen. Just click on
and the drawing reappears.