The line of symmetry move when I adjust the size I created a cube and then 'ctrl + R' to create a line of symmetry for the cube (Vertical). Then I 'x' to delete the left vertical and add a modifier of mirror so that the cube could be adjust by only changing one side. But when i try to adjust the size by 's', the line of symmetry will move with other line as well, which I did not expect to happen. As shown:


But actually I want something like this:


Have I done something wrong?
The easiest way to fix weird mirroring is to create a new empty and use that as your line of symmetry by selecting it under Mirror Object



If it doesn't work as you expect this is usually faster than messing around with whatever it is.