Moving a line end

The line ends are automatically moved when you move the line segments. You can also move a line end directly.

Click on an ending point of a line and keep the mouse down. The cursor will change from the Normal Select to Move. All possible locations of this ending point will be marked by small red circles. They are always seven such locations, one on the left and right side of an icon,  two above and three below the icon. You cannot move an ending point to another icon because you cannot change the order of steps determined by the connecting lines..  

Now, drag the ending point to another possible location. A dotted line will show the shape of the resulting line.              

In order to modify a line you have to drop the line end in the selected place.