It would be nice to be able to plot arrows not connected to nodes. For example, if you would like to show a timeline with events, where events are marked with an arrow, it is cumbersome that you have to make invisible notes in the ends of each arrow.
An example of a timeline plot, which I occasionally make in yEd can be seen in the following. All arrows down to the timeline is connect to invisible nodes.
It is possible to draw unconnected arrows. Just create arrow from/to same object, add middle point to line and move end of arrow to empty space: